By Richard Westcott - BBC transport correspondent
Two and a half years ago, the fledgling romance between the Conservatives and the Liberal Democrats was hitting the rocks. They were bickering about a runway. Having ditched Labour's plans to expand Heathrow, the pressure was back on ministers to consider growing it again, or if not Heathrow, then another airport in the South East. Business leaders were queuing up to tell them the country was haemorrhaging billions in lost trade because of a lack of connections to hot economies such as China and India.