General defense of an interocean canal was a concern of the United States government before, during, and after the actual acquisition of the Panama Canal Zone in 1903. But defense of the Canal against a threat from the sky was not an immediate cause for anxiety, for aviation as a military weapon or transportation boon was slow to develop after the first manned heavier-than-air flight in 1903. In April 1913, however, a U.S. civilian aviator, Robert Fowler, made the first flight over the Panama Canal. His flight generated enough alarm in governmental circles to bring about the initial regulatory measure pertaining to aviation and the Canal, an executive order of 7 August 1913 prohibiting unauthorized flights over the Canal Zone. During World War I various other Presidential orders broadened the original one. After the war the government allotted an Air Service observation group and a small number of Navy planes to the Canal Zone.² These and antiaircraft batteries were to provide an air defense that probably was sufficient for any practical assault that could have been mounted at the time.

By 1922 a few Army airmen as well as a few diplomats and politicians saw the need for additional defense for the Canal because of certain European commercial endeavors in Latin America, mainly originating after World War I: the sale of civil and military aircraft and the establishment of flying schools and rudimentary airlines in an area that needed air transportation but had little aviation of its own. In the first few years after the war the United States had been little interested in this competition for aviation sales and service. In December 1922, however, the United States Minister to Guatemala, Arthur H. Geissler, sounded an alarm to the State Department about European aviation activities in Central America. He coupled his warning with suggestions that the United States establish its own airline services in Central America and that military and naval planes from the Canal Zone be sent on missions of courtesy to Central America.³

Motivated by the warning, Secretary of War John W. Weeks soon wrote Secretary of State Charles Evans Hughes that there was a genuine threat to the Canal from commercial planes potentially convertible to bombers. He stated his opposition to any but United States control of airline service in Central America. The Chief of the Army Air Service, Major General Mason M. Patrick, had assured him, Weeks informed Hughes, of the availability of private U.S. capital and personnel if such an airline proved feasible. Concerning Geissler’s suggestion that planes be used in diplomacy, Weeks reported to the State Department that five Air Service planes were available in the Canal Zone for missions of courtesy to Central America. He pointed out that the logical time for such flights would be between November 1923 and April 1924, when the weather would tend to be favorable.⁴

Washington had thus decided to use the Air Service as a diplomatic instrument to counteract the alleged threat to the Canal. It did not take an entirely new orientation for the Air Service to assume this duty. Since the war various individuals in that service had been interested in Latin America as a logical area for the expansion of United States aviation. They had advocated official air missions or displays of U.S. aviation products at expositions attended by Latin Americans. On the other band the Air Service had at times failed to take advantage of such opportunities to promote U.S. aviation.⁵

What kind of environment were foreigners to encounter in Latin America following World War I? The influence of the industrial revolution, given impetus by World War I, was at work in parts of Latin America. The area had over a century’s history of attracting foreign investments, necessary for its development. A dubious effect of foreign investment was that it sometimes served as one prop for ruling oligarchies and caudillos. Many countries in the 1920s continued to welcome foreign loans, private and governmental, and various other forms of investment, while a few, like Mexico, were taking steps to limit investment. The Mexican attitude had contributed to a time of tension with the United States.

Certain past U.S. policies, like the Roosevelt corollary to the Monroe Doctrine and Dollar Diplomacy, had provoked increasing Latin American ill will toward the northern neighbor. The continued occupation of Haiti and broadened involvement in Nicaragua beginning late in 1926 were other examples. During the 1920s these policies underwent change, however, as evidenced by the Central American Flight in 1924, the Pan American Flight in 1926-27 (about which more later), and as climaxed by the Good-Neighbor Policy of the 1930s.

It was in a milieu of some tension, then, that the Air Service prepared to involve itself in a Latin American diplomatic mission. Flights of planes from the Canal Zone to surrounding Latin American areas for official purposes were not new in 1923. Navy planes from the air station at Coco Solo, C.Z., had previously flown to points in South America on courtesy visits. These flights had aroused enthusiasm among South American businessmen for aviation. The proposed Army venture, however, had wider implications. In a letter of 17 July 1923, Weeks outlined to Hughes the purposes of the projected flight to Central America: (1) sowing of good will, (2) charting of air routes and gathering of data on available airfields, (3) serving as forerunner of a United States airmail service from New Orleans to Central America, and (4) aiding the United States aviation industry to establish a market in Central America. Samuel S. Bradley, post-World War I figure in the United States aviation industry, recognized early in the era that "only through the development of commercial aviation will we be able to maintain a sufficient aeronautical establishment to meet the needs of national security."⁶ In seeking to promote overseas sales of American aviation products by the Central American Flight, the Air Service gave evidence that it had come to appreciate fully the relationship of a healthy industry to preparedness.

In August 1923 the Adjutant General of the United States Army authorized the Commanding General of the Panama Canal Department to send three planes to Central America for visits of courtesy and for charting "such airways in the Central American Republics as would be of value to the respective governments as well as to the Army Air Service in the event of an emergency…."The flyers also were to collect photographic data in support of airways reports. The air route to be surveyed was to run no farther north than "the southern Mexican border."⁷ Although not previously cited as a motive for the flight, the existence of airways for "emergency" use was to become of prime interest to the Army. This motive will be apparent in the subsequent account of Pan American Airways in Central America. Such an airway naturally related to the general theme of protection of the Canal.

As a companion project to the Central American Flight, Secretary Weeks suggested that treaties be sought with Central American countries for the exchange of aviation privileges and for mutual regulations pertaining to airplanes. The Air Service influenced this suggestion. General Patrick had been one of the U.S. delegates to a meeting in Paris in 1919 at which the first major international aviation agreement, the Paris Convention, was written. It was the basis for exchange of aviation privileges between contracting countries but at the same time asserted that a nation had sovereignty over its airspace. The United States had signed but for various reasons had never ratified the convention. The Air Service believed that expansion of U.S. aviation was limited by the failure to ratify. Individual treaties with Central American countries were to serve in lieu of ratification of the Paris Convention by these countries and the United States. Post-master General Harry S. New and Commerce Secretary Herbert Hoover favored these treaties, but Secretary of the Navy Edwin Denby presented the objections of the influential Navy General Board to the effect that reciprocal agreements might boomerang against the United States in the long run. Whether or not the Navy attitude was decisive, the treaties never developed. When it was evident they were a dead issue, General Patrick expressed his disappointment. They would, he believed, "afford to our Nationals the requisite assurance of their right to the continuing operation of such aerial transportation lines as they may see fit to establish in these Republics…"⁸

Thus the flight remained the central focus of the project. Hearing of the plans for a flight, the aviation industry’s Aeronautical Chamber of Commerce wrote to the Information Division, Army Air Service, requesting that the flight commander disseminate accurate facts about the United States aviation industry and gather data on the market potential in Central America. In reply the Information Division stated that one mission of the flight was to gather information that would aid the United States aviation industry but that it could not go beyond this, for the main objective of the flight was to disseminate good will, and Central American countries would resent an "advertising campaign" carried on by a "purely mercenary expedition…."⁹

Certain events in 1923 and 1924 made the flight seem urgent. In 1923 the Republic of Panama initiated negotiations with the United States for a recognized voice in matters pertaining to aerial navigation in Panama. United States officials in the Canal Zone, including Department Air Officer Major Raycroft Walsh, were cautious in the beginning talks, desiring control of aviation in all of Panama to protect the Canal. These talks soon became part of general United States—Panamanian negotiations toward revising treaty arrangements with respect to the Canal Zone. At some point in 1923 an airline company in Colombia, La Sociedad Colombo-Alemana de Transportes Aéreos (Scadta), commenced to apply pressure on the United States government for landing privileges in the Canal Zone. The Canal Zone was a requisite stopover for a survey flight preliminary to an extension of Scadta’s services to the United States via Central America and the Caribbean. Domination of Scadta by German and Austrian interests made its overtures especially unwelcome to United States officialdom. These events were perhaps capped early in 1924 when the chief umpires of the recently completed joint Army-Navy maneuvers in the area stated that air attacks against the Panama Canal would have an excellent chance of success.¹⁰

On 4 February 1924 Major Raycroft Walsh led the Central American Flight of one Martin bomber and two de Havillands on a journey that was in many respects a considerable undertaking. The flyers were not the first in Central America, but they were the first to attempt an elaborate diplomatic flight on a rigid time schedule. The lumbering Martin set an uneven pace that made it difficult to estimate the time of arrival at stops, where expectant crowds and tense officials waited. An ironic contrast existed: the flight carried radio equipment with which it performed plane-to-plane and air-to-ground experiments, but the maps of the navigation officer were not aerial maps, and landing fields were often primitive. In a sense the flyers were hostages to wild terrain, jungle, swamp, volcanoes (the latter "fat and majestic" in the words of the navigation officer), and on one occasion to some of the roughest air many of them had ever encountered.¹¹ Like the conquistadores of old, they were explorers with political motives.

In spite of the impediments, the flight proceeded up Panama to Costa Rica, Nicaragua, El Salvador, and Guatemala, avoiding Honduras, where there was revolutionary turmoil. At each stop cordiality and enthusiasm were evident. Through a misunderstanding, the Nicaraguan chief executive was not on hand on the outward journey, but he gave a banquet for the flyers on their return trip and went up for a joy ride. In Guatemala, President José Maria Orellana led the crowd in three cheers for the United States, a compliment the aviators did their best to return. Although wearied by flying and the demands of formal and informal receptions, the flyers, according to observers, performed with finesse. Central Americans were particularly impressed by the fact that the visitors managed to arrive at scheduled stops on time. They were undoubtedly impressed by another statistic: the flight returned to the Canal Zone on 24 February 1924 without serious accident or loss of life.¹²

In his official report Walsh pronounced the goodwill and route-chartering phases of the mission accomplished. To expedite the successful conclusion of the other two phases—a United States airmail service to Central America and aid to the American aviation industry —he recommended that the United States send official air missions to Central America to offset the influence of Europeans, whose aviation activities in Central America the flight had affirmed, and that the United States government promote an airline, either official or private, in the area. Such a line would have to connect with both the United States and the Canal Zone to be profitable. To boost its aviation industry, the United States needed to establish service and supply facilities in Central America and choose with care a plane for the airmail service.¹³

The Central American Flight was the pioneer effort of major good-will endeavors in Latin America by the Air Service and its successors. It had another and broader importance for the future: the flight was a harbinger of the Good-Neighbor Policy and its subsequent variations, whereby the United States recognized the value of demonstrated good-will.¹⁴ It cannot be denied that the flight was also in certain respects a continuation of Dollar Diplomacy, in that it sought to promote American economic investment in Latin America for the advancement of diplomatic aims. But an avowed and sincere objective of Walsh and his men was to spread good will. The success of that objective is revealed in the Central American response to the flight.

The aftermath of the flight, however, was for those who desired a successful outcome a story of apathy, frustration, and delay. Secretary Weeks’ reaction to Walsh’s report did not contain the urgency he had expressed earlier. While Weeks advocated some type of action, he stated that no authority existed for air missions to Latin America. It was not until six months after the flight that an interdepartmental conference met in Washington to discuss the matter. Meeting on 20 August 1924, with Walsh representing the War Department, the conference recommended that the Post Office Department investigate the practicality of an airmail route to Central America.¹⁵

Accordingly, the Post Office Department selected postal specialists Vincent C. Burke and Joseph V. Magee to conduct an investigation. They were supplied such pertinent information as the high degree of interest in Central America for an airline and airmail service. The Mexican ambassador indicated that his country might cooperate in the establishment of a route. United States diplomats repeated Walsh’s point that a successful airline must connect the United States and Panama. Even then, they warned, the line might not pay at first, but military and economic reasons made the route imperative.¹⁶

In November 1924, after arriving in the Canal Zone, Burke and Magee consulted with various officials, among them Major General William Lassiter, commanding the Panama Canal Department. Lassiter pointed out several benefits to be derived from a Panama—United States airline. He suggested that its facilities would be especially beneficial to the Air Service in wartime. After a short stay in the Canal Zone and a quick visit to Costa Rica, Burke and Magee returned to the United States. In their report they stated that they found from statistics in the Canal Zone, from talks with officials, and from the trip to Costa Rica that an airmail service was not economically feasible and so, from a postal standpoint, not justifiable. They offered the view, however, that the service was probably justified from a strategic standpoint. Thus they did not reject an airline out of hand, but the report set off a chain reaction that brought a halt to progress. Postmaster General New felt that further action was not "desirable……at this time." On the basis of this decision by the Post Office Department, both the State and War Departments decided to terminate their efforts. But it was not without protest from the Air Service. General Patrick felt the investigation was not a true test, for the inspectors had not gone to Guatemala, where sentiment for airline service was the strongest.