The largest airmail customers were in the banking business. They used the service to send checks and financial papers more quickly. Bankers wanted to reduce the float time of checks and pushed for an extension of routes. Financial papers were light, and the cost to send them was low—just 16 cents an ounce, having been reduced from 24 cents in July 1918 to attract more customers. It was further reduced to six cents per ounce on December 15, in an effort to draw even more customers. In July 1919, the extra charge for airmail was eliminated completely and airplanes began to carry a random selection of mail. The charge would be reinstated in 1924 when regular transcontinental service began.

Postal aircraft could fly with sacks of mail for an average cost of $64.80 for each hour in the air. Pilots received a base pay of about $3,600 per year and then were paid five to seven cents more for each mile they flew, flying an average of five to six hours each day. After a year in operation, postal revenues for the year totaled $162,000. The cost to fly the mail had been just $143,000. This first year of operation was to be the only time in airmail history that the service showed a profit.