B&W Foldon Box for Brompton
This nifty folding box will fit your Brompton and protect it during transit.
It's possible to carry it on the rear rack of a Brompton, underneath elastic straps. That way you can ride to the airport!
It's made of polypropylene / ABS plastic, so it's tough. It also comes with foam pads on the inside to protect your precious cargo.
The bottom of the box has 4 castors (2 fixed a the rear, 2 turning at the front) and a padded strap to roll it along behind you. It's easier to roll than the B Bag.
Fits some other folding bikes too (but why wouldn't you just get a Brompton?).
Dimensions (folded):68 x 20 x 34.5cm
Dimensions (assembled): 68 x 78 x 34.5cm