You can do it in person and it takes about half a day of waiting to get it done. You have to call and make an appointment at the local US passport office (if there's one near you) and go. Once you turn in your old passport, they'll still take some hours before the new one is ready. You need to get a letter from basings office saying that you're a pilot employed with xx airlines etc... they get this request often and have a pre-typed letter ready to send and will email it to you. The passport office will want this letter when you show up at your appointment. Take your printed schedule too.
Don't fall for the gov. authorized private passport shops that will FEDEX the passport overnight etc..., they will charge you two arms and and a leg. They try real hard to make their ads look like it's the US passport agency itself. Welcome to America where everything is for sale and there's no limits to outsourcing, even when it comes to issuing passports.
