> NYC to London

No A380s on this route. There are 32 flights each way, 28 from Heathrow.

BA/AA operate 12 daily flights LHR-JFK, pretty much one ever 90 minutes during the day, it's pretty much a turn up and go service. Virgin/Delta do another 8 flights, again turn-up and go.

That frequency attracts the people on flexible tickets. Those on the cheapest flights they find on skyscanner will probably take the norweigan 787s from Gatwick.

That market for flexibility doesn't exist between say London and Singapore (I suspect most are transferring at least at one end), but there's plenty of passengers looking to travel, and so you get 4 of the 7 flights over 3 carriers are on A380s.

> it's pretty much a turn up and go service

Assuming you have a flexible ticket, which the overwhelming majority of passengers don't.

Tried asking BA/AA to move to an earlier flight on a non-flex ticket? "Computer says no, unless you pay $lots"

On BA all business class tickets are changable for a nominal fee (about 5% of the cost of a return ticket). It's that flexibility that means people pay £6k return for the cheapest business class LON-NY ticket.

Sure, if you're flying on the "cheapest flight on skyscanner" then you don't get the flexibility, but that's why they don't fly 6 A380s rather than 12 smaller planes, they want the £6k tickets to choose BA/AA rather than VS/DL. The £600 return tickets at the back will fly whoever's cheapest.

>> BA all business class tickets are changable for a nominal fee

That's a sweeping claim.

Pick a highly-discounted business class fare LON-NYC-LON for dates well in advance which books into I fare bucket.

I close the ILX1C1S6 fare, out 25 Dec 2019, back 1 Jan 2020. (The base fare is GBP1271 r/t...)

Either do a dummy booking at BA.com, or go to ExpertFlyer[0] and the fare rules. Find the 'PENALTIES' section:

  CANCELLATIONS
   
     ANY TIME
       TICKET IS NON-REFUNDABLE.

[...]

  CHANGES

     ANY TIME
       CHANGES NOT PERMITTED.

[0] www.expertflyer.com

I looked at a selection of business class fares (including fares booking into I buckets) a couple of weeks in advance and all were changeable for £300.

"Almost all" then, especially when you factor in corporate deals

Which route(s)? Were you including a Sat night stay?

At BA.com I've just looked up LON-NYC-LON out 6 Mar back 13 Mar (so just over two weeks from now), and I'm seeing the same complete lack of flex:

Your ticket conditions

Changes to your ticket No changes permitted. No upgrades permitted

Refunds There are no refunds except for any government & airport taxes

Also I guess if you are running 12 flights you can adjust the number to demand and say do 10 or 8 in low season. It'd be less easy to do that with the A380.

If you have somewhere else for the planes to go, and the slots and agreements, yes.

BA ran an empty flight from Heathrow to Cardiff for a while to keep a slot at Heathrow.

Where capacity allows, serving a route multiple times with small planes is preferred by airlines and customers. And even if slots are restricted, offering less capacity than demand (driving up prices) can be more profitable than trying to offer service to anyone who's willing to book.

Long range versions of single-aisle planes also change the dynamics a bit, putting less focus on hubs.