For customers who cannot obtain a travel itinerary, the U.S. Passport Agency will accept a company letter to be used in the place of airline tickets or a travel itinerary.
The letter must contain the following:
The letter should be written on company letterhead
The name of the passport applicant employed by the company
The country to be visited
The applicant’s date of departure (if you may travel at any time, indicate the earliest approximate date)
The letter must be signed by someone other than the applicant
Note: You cannot sign your own letter and departure date in the letter must be within 14 days.