Now all this skill and billions of money have been invested in the industry so that the plants in this country have the capacity to manufacture nearly two hundred a day. With this nucleus to start a peace-construction programme the price of even the biggest machines must soon shrink to that of a high-priced automobile or private yacht. Plenty of sporting machines with a small wing spread and a two-cylinder motor that will sell for five hundred dollars are now being made; and since these machines can average twenty-two miles on a gallon of gasoline the expense of maintaining one of these will not be out of the means of hundreds of the young flyers who have returned from flying on the West Front. Moreover, since there will be no maintenance of roads, rails, live wires, and so on, such as there is in the railroad and electric road industries, the cost of aero maintenance is infinitely smaller, so that aerial travel may become cheaper than any other known to man. Fundamentally, the hydroaeroplane is the same as the aeroplane except that pontoons instead of wheels are used to land upon. The cost of these airships over the land machines is noticeable only where boats are used instead of pontoons. Consequently, their price above the aeroplane will depend on the size and the kind of furnishings used in the boat. Owing to the fact that no landing-field has to be bought and maintained and that the flying-boat can come down on a river or a lake with comparative ease, and also the fact that altitude does not have to be maintained in order to glide to an aerodrome or a safe landing-field, this type of aerial navigation bids fair to be fast, cheap, and absolutely safe. Moreover, the size and passenger-carrying capacity of these flying-boats will be limited only by the construction of wings strong enough to maintain them in the air, for the size of the hulls and the number of motors can be increased indefinitely.