I must say, I've often wondered if the idea of ATA fueling was abandoned to early in civil aviation. If the initiatives of the 1930s' had been continued, we might now be in a situation where the infrastructure/saftey/training issues had long been resolved.
I've also wondered how much more viable Concorde may have been had it had the unlimited range ATA provides.
I agree that, as it is such a fundimental change in the way civil aviation operates, it is unlikely to ever be implemented, but iti is never the less an interesting concept.
As to the extensive training required, during the Falklands conflict the Vulcan pilots who staged the quite incredible missions from UK bases had never ATA refueled until two days before the mission!
Amasing whet can be achieved with sufficient will.