I write this to my guests via the Airbnb email system:
“What time on (day) will you be arriving? May I please have the name of your airline and your flight number so that I can track your arrival status.”
When they arrive I ask them what time their flight is on the day they are leaving. However, bear in mind that arrival and departure times (arrival times in particular) change. Yesterday’s guest asked if she could arrive between 11:00 A.M. and noon. I told her that would be fine, but that unless the prior night’s guest left very early the guest room wouldn’t be ready. At noon, she emailed to tell me that it looked like she would arrive around 3:00 P.M. She arrived at 2:00 P.M.