Then comes the question of passports, customs, registration, safety precautions, and damages. As already shown, the man on the ground is helpless against the airplane which chooses to defy him. People and goods can cross national lines by the air without passports or customs. There will be no main ports of entry as in sea or train commerce, and it is too much to think that any nation can patrol its whole aerial frontier in all its various air strata. Undesirable immigrants or small precious freight can be smuggled in with the greatest ease through the route of the air.

Obviously the most elaborate international rules are necessary. Planes must have some method of international registration and license, just as in a more limited sense ships on the seas have what amounts to an international status. Landing-fields must be established and open to foreign planes, each nation providing some kind of reciprocal landing rights to other nations. Arrangements must be made so that if a monkey-wrench drops out of a plane a mile or two up in the air proper damages can be collected. For such things there is to-day but little precedent in law.

This but sketches the problems. It shows, however, how closely this new science will bind the world together and obliterate national lines and nationalistic feelings. As the sea has been the great civilizer of the past, so the air will be the great civilizer of the future. Through it men will be brought most intimately in touch with one another and forced to learn to live together as they have not been forced to live together before. The artificial barriers that have stood so firm between nations in the past are now swept away and a great common medium of intercommunication opened.

Let it not be understood that all this will take place overnight. Far from it, for the experience of the war has taught only too well that the organization of an air force takes time and patience. Up to date the essential fact is that the science, the value, and the possibilities of flight have been proved in a thousand different ways. Vistas of travel and experience have been opened up which but a few months ago would have seemed fanciful. Everywhere men are dreaming dreams of the future which challenge one's deepest imagination. Already Caproni, the great Italian inventor, has signed a contract to carry mails from Genoa to Rio Janeiro.

Now comes news of an airplane with room for ninety-two passengers. Engine power and wing space have gone on increasing in a dazzling way till one is almost afraid to guess what the future may hold. But, omitting all prophecy, the actual accomplishments to date are so stupendous that there is no need to speculate as to the future. If all technical development were to stop just where it stands, the factories and workshops of the world could well be occupied for years in turning out the machines necessary for the work awaiting them. Scientific development has gone so infinitely far ahead of actual production that as yet aviation is not being put to a fraction of its use.

Even more serious, however, is the general public failure to realize the gift which is within their reach. Flying was first a circus stunt and later a war wonder. The solid practical accomplishments have been lost sight of in the weird or the spectacular. People who marveled when a British plane climbed up nearly six miles into the air, or 30,000 feet, where its engine refused to run and its observer fainted, failed generally to analyze what the invasion of this new element would mean in the future of mankind.

What is now needed is a big, broad imagination to seize hold of this new thing and galvanize it into actual every-day use. There are many skeptics, of course, many who point out, for instance, that the element of cost is prohibitive. This is both fallacious in reasoning and untrue in fact. A modern two-seated airplane, even to-day, costs not over $5,000, or about the price of a good automobile. Very soon, with manufacturing costs standardized and the elements of newness worn off, this price will fall as sharply as it has already fallen during the war.

But what, after all, is cost in comparison with time? Modern civilization will pay dearly for any invention which will increase ever so little its hours of effectiveness. The great German liners before the war lavished money without stint to save a day or two in crossing the Atlantic. The limited express trains between New York, Boston, Washington, and Chicago have for years made money by carrying busy men a few hours more quickly to their destination. What will not be paid if these times of travel can be reduced practically to half?

The element of danger has been reduced to a minimum and will be still more reduced as emphasis is laid on safety rather than wartime agility. Many men, of course, will meet their death in the air, just as in the early days many men met their death in ships and in railroad trains, but this will not be a deterrent if the goal is worth attaining. There will be accidents in learning to fly, there will be accidents of foolhardiness and of collision or in landing, but they will decrease to the vanishing-point as experience grows. Already the air routes which have been established have a high record of success and freedom from fatalities.

The great need of aviation to-day is faith—faith among the people, among the manufacturers, among the men who will give it its being. Its success is as inevitable as that day follows night, but the question of when that success is attained, now or generations from now, is dependent on the vision which men put into it. If they are apathetic and unreasonable, if they chafe at details or expect too much, it will be held back. If, on the other hand, they go to meet it with confidence, with coolness, and with a realization both of its difficulties and its potentialities, its success will be immediate.