Can I get a re-entry permit at Don Muang Airport and what is the process?

Yes, you can obtain a re-entry permit at Don Muang Airport. Inform the officer at passport control of your need for a re-entry permit, and you'll be directed to a specific counter for re-entry permits. The fees for a single re-entry permit is 1000 baht, while a multiple entry permit costs 3800 baht, which is the same as at immigration offices. You need to fill out a form and provide a photo; alternatively, for an additional 200 baht, you can simply present your passport and they'll assist with the necessary documentation.