However, an industry source said in this case, the “road” was more like a toll road, as the cash-strapped Ukrainian government was receiving overflight fees for each commercial flight above its territory and therefore had a financial incentive to keep the airspace open as long as possible. Tributes to MH17 victims at the Netherlands Embassy in Kiev. Three days before MH17 was apparently shot down by a surface-to-air missile, Ukraine had raised the minimum altitude open for commercial flights over the eastern part of its country to 32,000 feet, from 26,000 feet previously after a military cargo jet was downed at 21,000 feet. The Malaysian Transport Minister, Liow Tiong Lai, said on Saturday that the pilot had requested to fly at 35,000 feet over Ukraine’s airspace but was told by air traffic control to fly at 33,000 feet. It is unclear, however, whether flying at a slightly higher altitude would have made any difference in this case as the BUK missile system that allegedly shot down MH17 can hit targets with an altitude of up to 75,000 feet.

A graphic compiled by German magazine Der Spiegel with data from FlightRadar24 showed Malaysia Airlines was not alone in flying over eastern Ukrainian airspace in the week before MH17 was shot down. Despite the ongoing conflict with Ukraine, Russian national carrier Aeroflot flew over the area 86 times, while Singapore Airlines did so the second most at 75 times. Other carriers that used the airspace included Lufthansa, Thai Airways, Qatar Airways, Emirates and Etihad Airways. However, British Airways, Air France and Cathay Pacific were among the major carriers noticeably absent from that routing. The Emirates president, Tim Clark, said MH17 had “changed everything” for his airline. “We will no longer rest on protocols we had in place that we honestly thought were safe,” he told the Wall Street Journal.

Owen Zupp, the author of The Pilots Blog, said Malaysia Airlines and others had been within their rights to fly over eastern Ukraine given it had been deemed safe to fly by IATA and the International Civil Aviation Organisation. “However, some of the factors to be considered were undoubtedly the restricted airspace below the route and the reason for that restriction and the warnings that had been issued regarding operations in the region,” he said. “These warnings had prompted other airlines to avoid the Ukraine airspace. There is also the apparent shooting down of other aircraft in the area and the feasibility of flying alternate routes.” Mr Zupp said there were undoubtedly real threats to consider prior to the loss of MH17. “That flight through the area may have been legal, but one must wonder whether it was prudent?”