THOMAS Cook is planning to make more than one in seven of its airline workforce redundant in a bid to reduce costs.

The struggling tour operator says about 430 jobs are at risk as it aims to reduce the number of planes it operates from 35 to 31, as leases on four aircraft expire.

The UK's second biggest travel firm has launched a consultation on redundancies, with pilots and cabin crew among those likely to be targeted.

Thomas Cook currently operates from three bases in the UK – Glasgow, Gatwick and Manchester – and flies from 21 airports, also including Edinburgh and Aberdeen.

It has around 300 staff based in Glasgow, though the numbers vary depending on the season.

But the firm said customers would not be affected and that its holiday programme for 2013 would be delivered in full.

The gaps in its flight schedule are due to be filled by a greater reliance on third party airlines such as EasyJet carrying its customers.

The group, which was recently forced to turn to its banks for an additional £200 million of loans, has scaled back the size of its own airline in the past year and entered into a partnership with the discount travel firm.

Thomas Cook's air travel division currently employs just over 3100 staff and the cuts will be made among flight crew across the department.

Christoph Debus, group head of air travel at the company, said: "This is a very difficult decision, but necessary to deliver a successful transformation and build a sustainable business for the future, which will continue to offer opportunities for the 2700 people employed with us after these proposed changes."

The group said its airline, which last year flew 6.8 million passengers, will continue to serve all of its key routes.

Thomas Cook was plunged into crisis last November after it turned to its lenders for help, sparking fears of a collapse.

It appointed former Premier Farnell boss Harriet Green to lead its turnaround as its chief executive.

As well as reducing its aircraft fleet, it has sold five Spanish hotels and its Indian arm as part of the strategy to reduce its £1 billion debt mountain.

Ms Green is expected to unveil the initial findings of her review alongside full-year results in November.

A spokeswoman said the vast majority of its flying programme would still be provided by Thomas Cook Airlines.

She said: "The vast majority of our flying programme will remain in-house and concentrated around core routes, while developing the use of third party flying gives us flexibility to meet changing demands and take steps to address the imbalance between the UK's summer and winter flying programmes."

Aviation experts said the company had been hit by a long-term shift in travel habits away from package holidays and in favour of people booking their own flights and accommodation, while the economic downturn has also hit profits as fewer people are taking holidays.

One industry source said the proliferation of online hotel booking websites had accelerated this trend, as holidaymakers found it easier to book their own accommodation.