answer: #Person2# is going through the check-in procedure. #Person1# lets #Person2# check the backpack. #Person2# asks for an aisle seat and asks the latest time to board the plane.
documents: #Person1#: May I see your ticket and passport, PLS?
  #Person2#: Sure, here they are.
  #Person1#: Any luggage?
  #Person2#: Just this suitcase.
  #Person1#: Your backpack is very big and today's flight is quite full. I am afraid that you will have to check your backpack too.
  #Person2#: No problem. What about this carry-on?
  #Person1#: You can take that with you.
  #Person2#: Can I have an aisle seat, PLS.
  #Person1#: No problem. I'll give you an aisle seat in the center row. And here is your ticket, passport and boarding pass. Please board the plane at Gate 15.
  #Person2#: Thank you. And when is the latest time for me to board the plane?
  #Person1#: 15mins before the plane takes off. The plane is scheduled to leave on time.
  #Person2#: Thank you very much!
  #Person1#: You are welcome! Have a nice flight.