seatmate

listen to the pronunciation of seatmate
Английский Язык - Английский Язык
A person that one sits next to

My seatmate on the airplane snored incessantly.

A person that one shares a seat with (such as a bench or other surface that seat more than one)
the person who sits next to you on a plane
A person you sit next to
A person you share a seat with (such as a bench or other surface that seat more than one)