Several flights from Terminal 5 to Scotland have been cancelled
Scottish business leaders have claimed that Scotland has been disproportionately affected by the problems at Heathrow's Terminal 5.
Glasgow, Edinburgh and Aberdeen airports have all seen the cancellation of some scheduled flights.
British Airways has denied a disadvantage to Scotland over the past two days.
First Minister Alex Salmond said Scottish passengers were getting "fed up".
He added: "Filtering everything through Heathrow leaves us extremely vulnerable, we need more direct flights and of course we should have a fast train service north to south."
BA has urged passengers to check for updates on its website.
Scottish business leaders have spoken of anger at the problems.
Andy Willox, of the Federation of Small Business Scotland, said: "It is an open secret that flights to and from Scotland are the first to be scrapped in order to clear the backlog and handle more lucrative international flights."
Liz Cameron, chief executive of Scottish Chambers of Commerce, added: "It seems once again that services to and from Scotland are suffering disproportionately."
Aberdeen MP Anne Begg insisted that she was boycotting BA flights to London until problems at the new terminal were sorted out.
Ms Begg, who uses a wheelchair, said she experienced a catalogue of incidents - including broken lifts and ill-informed staff - while trying to fly out of Heathrow on Thursday.
A spokesman for airport operator BAA Scotland said: "Anyone travelling with BA to Heathrow Terminal 5 should contact the airline before setting off, particularly if they are making a connection from T5 to another destination across Europe or long-haul."
BA has set up an information line for T5 passengers: 0800 727800
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