Swatch Moonswatch, mission to the moon, is a genuine, affordable replica of one of the most iconic aviation watches.
Seiko, Sports 5 GMT, is likely the most affordable, quality automatic GMT movement on the market. I recently saw one at the BX so you can probably find it tax free.
Casio is always an excellent choice, particularly if a model catches your eye. Citizen is an excellent choice above Casio. Both brands have some great options that offer a combined digital/analog face with solar charging and radio freq time synch.
My must have in a watch for work is a date and GMT function, and I prefer automatic/mechanical movements. I have never used the E6B on a watch I own, however if that's your thing it can be a cool feature.