After the world war i many ex pilots and their planes were hired by this

border patrol
federal express
u. s postal service
coast guard

The correct answer is C: U.S. Postal Service

In 1918, the Post Office Department took over airmail service from United States Army Air Service. Many ex pilots from the First World War were hired to help carry out the postal air deliveries. They had to have at least 1,000 hours of flying experience, some ex-Army aircraft was also purchased. The pilots were advised not to perform any stunts during flying and to fly in all weather conditions. This caused a lot of trouble as many pilots refused to fly under dangerous conditions, especially in fog. They were accused of not keeping to the postal schedule, many of the pilots resigned after such incidents. In 1919, the pilots went on strike, complaining of being forced to fly in zero visibility.

During 1918, 40 ex-Army pilots worked for the Postal Service.

answer: are there any

explanation: