HMRC published a report in October 2012 modelling the effects of price differentials at UK airports, including the effect of a price change at Scottish airports equivalent to the full value of air passenger duty. Figure 2 of the report gives a reading of the possible passenger response at Manchester airport.
A cross-party process reached the recommendation that Air Passenger Duty should be devolved to the Scottish Government. HMRC analysis of the potential effects on UK airports of price changes at Scottish airports aided the discussions behind this process. The analysis can be found at https://www.gov.uk/government/publications/modelling-the-effects-of-price-differentials-at-uk-airports
The Chancellor announced on 27 February that the Government will review potential options to support regional airports affected by devolution. As part of the review, the Government plans to publish a discussion paper by the summer examining the devolution and variation of APD rates within England, and the provision of aid for regional airports.