Fickes used the same technique more strikingly in the delivery flight of the larger Navy K-5 in 1941, when he flew in to Lakehurst from Wingfoot Lake at 100 miles per hour speed, again demonstrating that greater cruising radius than that for which a ship was designed may be effected, whenever it is possible to pick departure times that are most favorable. [Illustration: Ships like these, off New York City’s great harbor, might afford warning of the approach of enemy submarines, or the laying of mines to endanger its shipping.] [Illustration: Operating from a base across in Jersey, the blimps became a familiar sight around New York City during the World’s Fair.] [Illustration: While throughout the middle west, the long afternoon shadows marked the arrival in one city after another of strange visitors from the sky.] Other improvements in construction or operating technique grew out of the fleet’s experiences in flying in all weathers. A trip made by the Defender in 1930 from Miami across to Havana brought home the usefulness of the radio. The insurance underwriters insisted on a two-way radio being installed, along with pontoons on the ship, as safety precautions. Neither radio nor pontoons were needed during the crossing, but the pilots sensed the desirability of being able to communicate with their home station and their airport objective. Shortly after a short wave frequency was granted to the ships, one of the early ones in aircraft, and two-way sets were later installed on every ship, on the ground-crew buses and at Akron. This permitted the making of daily weather maps, extended the airships’ radius of action. Pilots would set out with more assurance, knowing that they would be quickly advised of foul weather ahead, could change their course, give appropriate instructions to the men on the ground, land whenever it seemed desirable. In the end the airships were all doing instrument flying, riding the radio beams like the passenger airplanes, got their landing and take-off instructions from the radio control towers at the airports. The fleet proved an ideal testing vehicle for the expeditionary mast. But progress moved carefully, a step at a time. As late as 1930 an air dock was built alongside the company’s plant at Gadsden, Ala., for use as an operating base in the middle south. It was thought necessary as a half way point for ships headed for Florida. After the high mast came in however, the Gadsden dock came to be used only for warehousing, and no airship has been inside it in four years.