Ecojet Airlines Ltd, a Scotland-based start-up backed by green energy entrepreneur Dale Vince, is being wound up after a court appointed a provisional liquidator, a Companies House filing showed. A provisional liquidator is an insolvency specialist who takes control while the court process runs. The failure lands at a tricky moment for small aviation projects trying to cut emissions on short routes by swapping out jet fuel. Ecojet struggled to raise funds, including £10 million required by the UK’s Civil Aviation Authority, Daily Business reported. Vince said he had paused his investment, adding “aviation is the last frontier and the hardest” and that cleaner flying was “a matter of when, not if”.