British Airways' transatlantic plans could be thrown into chaos as its US partner American Airlines (AA) files for bankruptcy protection - with debts of £19 billion.
The fourth largest airline in the world serves as a partner for BA on routes in and out of the US, but applied for protection while is carries out an emergency restructuring.
The airline this month launched a TV ad campaign featuring Kevin Spacey, but some city experts say the news could affect route services.
Andrew Fitchie, analyst at stockbroker INVESTEC, told The Sun: 'Ultimately this could affect what routes are being offered and the quality of the American product.
'They will not be able to invest in the service with this going on. It could also affect prices people are charged.'
AA has vowed to honour tickets and reservations, and chief executive Gerard Arpey said the goal now is to become 'more competitive'.
Back in March, BA joined its transatlantic schedules with AA, to spread flights throughout the day, creating a kind of 'shuttle service' between the two.
And BA is standing by its transatlantic partner, saying: 'We have a successful business together and believe this will provide us with an opportunity to get stronger.'
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