British Airways has sold the regional operations of its subsidiary airline BA Connect to Flybe, a move that will lead to about 900 flight cancellations.
BA has given Flybe around £130m to take its regional operations
Airports affected will include Manchester, Glasgow, Edinburgh, Birmingham and Bristol.
Here, travel writer Simon Calder explains to the BBC the answers to the key questions about the sale and its effect on UK air travel.
Why has British Airways sold its regional operations?
British Airways a year ago said that its regional flights - the ones linking for example Manchester and Birmingham, Glasgow and Edinburgh with other UK points and some other European points - were simply losing too much money.
So, they had this great idea, they were going to re-brand it as BA Connect.
This had a great slogan - 'New low fares, same good service'. Unfortunately, it was the same old losses.
Over the past year, they have been losing £1 every minute of every day - and that equates to a subsidy from the BA shareholders to each passenger of BA Connect of £10 each.
How much did Flybe pay for BA Connect?
Flybe haven't exactly paid for it. In fact, British Airways has had to give them roughly £130m to take it away.
So Flybe say we think we can turn it around - we are much more efficient, we can use better aircraft, we will be able to make a profit.
But actually, there are 15 routes - and these are the ones that sadly from this morning are being cancelled - which are losing so much cash that not with the best will in the world will they be able to turn them around.
So they are just going to close them down.
Are there going to be any new routes to take their place?
The big problem for Flybe and British Airways is the presence in the UK of Europe's two biggest and most successful low-cost airlines - that is EasyJet and Ryanair.
If they decide to set up a route, for example from Edinburgh to Zurich in the case of EasyJet or from Prestwick to Lubeck, which Ryanair says serves Hamburg, then there is very little that the regional airlines can do to compete because EasyJet and Ryanair's costs are just so low.
So what Flybe is saying is we think there are still routes where we can work because there simply isn't the demand to fill the aircraft of the big no-frills airlines.
They will be starting about 14 new routes but the old ones are just history.
What can customers who have BA Connect tickets do?
They can get their full refund and they may well find that the replacement flight is going to cost them rather more than they paid. There are going to be passengers like that.
What British Airways has been doing for the last two weeks, very quietly, is e-mailing passengers saying, look we are terribly sorry but we don't think this flight is going to operate.
This means for British Airways that they don't have to pay the compensation that would otherwise be due under European Union rules.
And also for the passengers it means they can decide to get a refund.
They can, for example if they were flying to Hamburg, fly via London instead, even though it takes twice as long.
There are also routes which are duplicated by Flybe and you can just transfer to a Flybe flight.
How do business customers feel about the cancelled routes?
The business community is going to be angry about that. They are the people who have been supporting British Airways regional routes for many years.
They have got used to just hopping on a plane, say between Southampton and Edinburgh provided by British Airways, and they are going to be very angry that they no longer can.