As I sat in a First Suite on a packed 744 yesterday enroute from San Francisco to Chicago and thought how fortunate I was not to be on one of the many 757s or Airbuses that also ply the route, I began to ponder how United manages to fill flights to capacity, whether the flight be on an A320 with 138 seats or a 747 with 347 seats -- with over 2.5 times as many seats (and over 7 times as many premium seats) as the Airbus.
The obvious answer is "inventory management," pricing the flights appropriately to meet demand. But how exactly does this work? Using some random dates, most flights cost the same, regardless of aircraft type and size. In my experience, it's not necessarily easier to book award seats on the larger planes either.
Granted, larger planes might fly at more popular times, but even this doesn't completely answer my question. For example, from SFO to IAD, United has a 777 at 7:54 a.m. and a much smaller 757 at 8:35 a.m. Would most people naturally prefer to fly on the flight 35 minutes earlier? (The flights usually priced out the same on my sample searchs, though in one case the 777 was more expensive).
Often, moreover, it doesn't seem like the bigger planes are flying when they do because it's a more popular time. The timing is based on the needs to route the aircraft through the domestic system between overseas flights.
My basic question, then, is how does inventory management ensure that both the 747 and the A319 are filled to capacity -- even though those capacities are extremely different?
What if the 2:05 p.m. SFO-ORD flight were scheduled as an A319 instead of a 747? Would the fares be higher?
What if United has dozens of extra 747's sitting around? Could they make every SFO-ORD flight a packed 747 (as UA870 usually is) and make a lot more money?
I know the answers seem really obvious, but I think there must be something deeper here than Economics 101.