A pilot taking the scenic route in his kit-built microlight drifted into a no-fly zone set up for an air show.

Alexander Stevenson's tiny Pridal Pulsar aircraft was spotted seconds before aerobatics pilots prepared to roar across the off-shore display area.

He had his father on board when their craft was spotted by the air show controller flying between 1,000 and 2,000ft through the zone, closed to air traffic by the Civil Aviation Authority.

The controller warned the pilot of an RAF jet who flew his plane alongside Stevenson's aircraft and rocked his wings - a warning sign to indicate he should leave the zone.

Thousands of spectators at the Airbourne Festival on Eastbourne seafront watched as the little plane was diverted clear.

The Civil Aviation Authority (CAA) launched an investigation following the drama in August last year.

Bank clerk Stevenson, 26, was yesterday fined after admitting flying within the restricted area.

Roderick James, representing the CAA, told Eastbourne magistrates event organisers spotted the light aircraft before the Red Arrows were due to launch into their 500mph display.

He said: "The RAF pilot had been in a holding area inside the restricted zone and was just about to leave when he was alerted to the fact there was another aircraft in the display area."

He said although the flying restrictions were temporary all pilots were legally required to read the Notices To Airmen (NOTAMS), which detail no-go areas, before taking off.

He also said Stevenson's radio was faulty - only receiving incoming messages - so he could not use it to check.

Ray Blount, defending, said Stevenson, from Ringwood, Hampshire, and his father, Michael, had been flying from Kent to Wiltshire when they decided to change course to admire the scenery.

He said: "They were originally going to fly cross-country on a route that took them near the Gatwick area.

"As they got towards Sussex they thought, because it was a beautiful day, they would change their route across the coast.

"They had not checked the NOTAMS for that area and did not know the air show was on."

Imposing the fine, Sally Wallace, chairwoman of the bench, said: "I'm sure you are well aware if you change your flight plan, you are supposed to make every possible effort to clear the route and make sure you are not going to be infringing any restrictions."

After the hearing, Stevenson said: "I have learnt my lesson and I will never make the same mistake again."

Their air show, which took place in August last year, attracted 650,000 people to Eastbourne.

Event organisers Eastbourne Borough Council said the incident caused a "small delay" and every precaution was being taken to ensure this year's show ran to plan.

A spokeswoman said: "We remind pilots of small aircraft to ensure they operate within the normal safety procedures."

Stevenson, of College Road, admitted flying below 5,000ft above sea level in a restricted area, at Eastbourne Magistrates' Court.

He was fined £250 and ordered to pay £350 costs for creating a "potential danger".