Taxi Service Achievement (Quick Method)

Find yourself a nice high mountain. On some servers you can fast travel to locations by holding G or H, look for location “Top”.
When their bring up the Buy menu by pressing B, go on Car tab and you want to buy Sukura Aguila Fort.
Have 3 players join you in the taxi and boost off the mountain, hold Shift and W till the achievement pops. I went so high I got I Want To Break Free achievement (Reach the upper limit of the sky in a plane)