Concorde, schmoncorde. At least that's what we assume Reaction Engines' A2 would utter if it could in fact speak. The supersonic jet, designed by Oxfordshire's own Reaction Engines, could one day shuttle passengers from Europe to Down Under in less than five hours, cruising at up to 4,000 miles-per-hour along the way. Granted, the aircraft is still in concept mode at the moment, but if all goes to plan, it could be operational "within 25 years." Reportedly, the 156-yard long jet could maintain a speed of 3,800 miles-per-hour -- over twice that of the famed Concorde -- and could carry 300 guests on each trip. Who knows how much a seat would cost, but we're guessing the sky's the limit. ...