supply is limited, slot trading became the main solution to enter Heathrow and transfers grew from 42 in 2000 to 526 in 2012 and over 10 years the average priced slot was equivalent to £4 per passenger. Reform In the United Kingdom, the Department for Transport has stated the slot system "is not designed to stimulate a competitive market environment and has no means of taking into account broader objectives". Reform could make the system for efficient, competitive and environmentally friendly. References Civil aviation