Wino,
Significant projects supported in the past include the Airbus A320 and A330/340 programmes. The A320 investment has already been repaid to government, and continues to provide a return. The A330/340 is contributing a steady stream of funds to the Exchequer, and is expected to pay for itself in the medium term. In November 1997, the Government reached agreement with Rolls-Royce to support the development of three new engines in the Trent family, for the Airbus A340-500/600, and for stretched and longer-range versions of the A340.
(Don't think the UK govt. paid anything towards the A300/A310....were BAE not a partner until the A320 days?)