Yep, U2 does have staff standby’s. They also have a very good confirmed staff seat system but that very much depends on whether the booking system has released staff seats. Their standby system however is very different to other carriers.
1. Only max of two staff standbys per flight at the booking stage
2. If the flight you booked on standby is released onto confirmed staff travel then your flight is confirmed at that stage.
3. Often you get confirmed at check in