Time is indirectly factored in via points. Take two pilots who have the exact same stats: a k/d of 2.5, a k/s of 1.5, and a k/t of 7.5.
Pilot 1 acquired these stats in 3 sorties(1.5 hours flying time) and has 4000 points.
Pilot 2 has these exact same stats but has flown 50 sorties(25 hours) and 65000 points. Because points is a category used in factoring rank, the second pilot will be ranked higher than the first one. In this way, time spent in the game factors in.
