Will the Passenger feat work with the Double-time feat?

For instance, I put passenger on rookie Vanisher, as well as Double-time. Can he then carry someone double his speed value, phasing as well?

Also, can transporters carry other characters while they're using double-time?

The answer here is yes and no. Double-time requires a move action, and is therefore not compatible with Phasing/Teleport, which requires a Power Action to activate.
However, Leap/Climb is a move action, and can therefore be used in conjunction with Double-time, including when using passenger.
Nope, as I explained above. He could either phase and carry at normal speed, or move at double speed without phasing or carrying.
A cheap Leap/Climber would do the trick though... R Spiler is probably the cheapest, 15 points for a 9 move with Leap/Climb ain't bad...
Doesn't say they can't, so I reckon they can...