Cape Town's Thunder City is to cease flying operations with immediate effect because the venture has become financially unviable, says founder and ceo, Mike Beachy Head. He cited in a statement a number of contributing factors, such as "the current slow economy, the high cost of maintenance, difficulties with inconsistencies from authorities and (negative) short to medium term prospects". He said Thunder City's 14 aircraft would be mothballed until a final decision was made about their future. Thunder City owns the world’s largest civilian-owned fleet of ex-combat jets, including three English Electric Lightnings, three BAe Buccaneers, five Hawker Hunters, a Strikemaster and two retrofitted Puma helicopters. Since its establishment in 2000, Thunder City jets have flown more than 2 000 sorties and generated revenue in excess of R100m. Beachy Head said flying enthusiasts ranging from celebrities such as Mark Shuttleworth and Sir Richard Branson to Middle Eastern sheiks, princes and European royalty had flown in the supersonic jets.   “Although this is the end of an era for flights in Thunder City’s fast jets, we will continue working on other internal engineering and development programmes currently under way. Who knows, if circumstances change, the mighty roar of the jets may be heard again at some time in the future,” he said.