Well at least you know for sure that she flew the coop. If you didn't know, it would be too late by the time you found out.
Perhaps she hadn't been mated and is trying to get more drone juice. Did she fly up or out low to the ground?
Drones fly high so a queen looking for mates will fly low for a good distance before gaining elevation so they're less likely to breed related drones.
If it were me, I'd order a new queen now. If she comes back, you could split some frames out for the new queen to make a third hive.
She flew out and up, fast. She'd have been mated, they come back with the abdomen of the male.
And I don't think I'm ready for a 3rd hive yet. I want to do a top bar hive, next.