Thousands of people attending this year's Lowestoft airshow will be urged to make a �3 minimum donation – amid warnings the event will cease to exist without more generous public support.

Planning is now all but complete for the two-day spectacular on August 11 and 12, with up to 400,000 people expected to gather on the town's seafront for one of East Anglia's biggest events of the year.

But although the show remains essentially free, the organising committee warned this week that there was now a genuine risk it would not continue unless people put more money in collection buckets.

Last year, the festival made a loss of �40,000 after suffering bad weather on both days, and this year, for the first time in its history, the show has been unable to secure a major sponsor.

In an effort to cover the �300,000 cost of running the event, organisers are suggesting a minimum donation of �3 per person – up �1 on last year.

Paul Bayfield, managing director of the Lowestoft Seafront Air Festival Ltd – the non-profit company organising the event – said: 'It is essentially a free event but if our bucket collection is low it simply won't continue.

'Increasing the minimum donation may be a contentious thing to do, but we've had a great deal of discussion about this. It hasn't been easy and we think if everybody gives a little, a lot gets done.

'We are starting this year in a position of weakness. As a consequence of that wet weather last year, we've suffered financially and we're now trying to get back to a position of strength. We need to hit the ground running if we want an event in 2012.'

The show organisers are also hoping that seafront businesses will contribute more to next year's show, after many once again failed to offer any financial support – despite reaping the benefits of extra custom.

Mr Bayfield said the committee had considered cancelling next year's airshow amid fears that many people might opt to attend the Olympic and Paralympic Games in London. However, it was decided a 'fallow year' could cause more harm than good and this would make it difficult to attract people and display teams, back for 2013, he added.

As if to illustrate the show's difficult financial position, it was confirmed this week that the historic Avro Vulcan bomber – an established favourite with air festival visitors – would not be taking part this year.

In a message posted on the festival's website, the organising committee explains: 'As the most expensive display we had last year – at �9,000 plus VAT per show – we felt that it was such a financial risk to book it again this year.'

Despite the Vulcan's absence, organisers have been able to secure a packed two-day line up and they are hoping the 2011 airshow will prove as successful as previous years when up to 450,000 people have attended.

For more information visit: www.lowestoftairfestival.co.uk