Each round can launch up to four planes. They are not all the same.
Regular planes use the standard crash mechanic. The multiplier climbs from 1.00x and you cash out before the plane crashes. If it crashes first, you lose that stake.
A Boost Plane adds a random bonus of 1.5x or higher to your win if you cash out in time.
A Double Plane doubles your bet automatically, so a successful cash-out pays on twice the stake you placed.
A Jackpot Plane puts every player in that round into the Double Heat progressive jackpot pots, Minor or Grand. Jackpot wins are separate from your cash-out. You can still hit a jackpot even if your own cash-out does not land.
Rounds run in real time. Other players betting the same round see the same plane outcomes as you. That is the multiplayer part: you are watching shared results, not a private single-player round.