Condor Venture pack is a clamshell of sorts. I have one for use as work EDC carries my work laptop and its equipment small FAK phone charger stuff. It been almost around the world, Israel, Spain, England, Ireland, Arizona, New Mexico, Oregon.
I believe the Arcteryx packs seemed to start this trend - often called “fileting” as well as the TSA inspection open packs. The TriZip style were pretty close too. I have used Vertx and Vanquest packs that open widely in the filet Style. Great for efficient and quick packing. They never feel quite as solid, but beggars shand’t be choosers.
Am I misunderstanding something? Clamshell backpacks for air travel were introduced by MEI in 1978 https://www.meipacks.com/products/mei-voyageur one year before the revolutionary business class by Quantas. The Tom Bihn Aeronaut has been around since 2006, the Red Oxx Sky Train only heaven knows since when. What Arcteryx...?