I usually call an embassy/consulate first if I have to arrange a visa in advance.
I take copy of standby itinerary, including ID90whatever or zed, as well as copy of husband's airline ID and marriage certificate. I actually had to get a Congressional letter to get same day/last minute passport services because we don't fit their "normal" circumstances. I usually get a letter from Chief Pilot's Office, regarding my husband's employment, asking for extended courtesies from gov agencies, etc. I'm sure your dept head has a form letter.
I take it you are not a US citizen?