I wouldn't worry about the price of international travel from the perspective of per plane capacity. A380 is dying because nobody wants it anymore. Slightly smaller planes are already more attractive to both airlines and passengers. Most don't want to go to a hub then fly out with 500 others at a big bang time they want to go more directly in smaller groups and/or at better times. It's not necessarily more expensive to do so depending on the plane, regional demand, and if you can drop that connecting flight. Similarly the demand for more international flights means more orders for planes not a need for more seats in each plane, and there is no reason to expect we'll suddenly stop being able to increase plane production for a decade and then be in trouble just because the market shifted towards not making mega planes anymore.