The review of previous research found consistent results showing that air travel price elasticities on short-haul routes were higher than on long-haul routes. This largely reflects the greater opportunity for inter-modal substitution on short haul routes (e.g. travellers can switch to rail or car in response to air travel price increases). While the geographical breakdowns outlined in the next section capture some variation by length of haul, there is still considerable variation within each market. In particular, very short-haul flights (approximately less than 1 hour flight time) are subject to greater competition from other modes.