Flying from Heho to Bagan with Air Mandalay involves flying via Mandalay.
I had an 11.45am flight from Heho to Mandalay and waited in Mandalay airport until about 5.30 for my flight to Bagan. Bearing in mind that Mandalay International airport is in the middle of nowhere, there isn't anywhere you can go! There is a café in the Airport called Kipling Café which charges 500 kyats for small bottle of water and 2500 kyats for a “Tuna’ sandwich, well that’s what it said in the menu!
On arrival into Bagan Airport you will be charged $10 USD for entering the Bagan Archaeological Zone.
There are plenty taxis outside the airport. The fare to New Bagan will cost you 6000 kyats, find someone to share with to cut your cost. Be aware that the taxi driver will pester you to use his services, this will include coming into your hotel to check your room number and possibly coming back the next day.