[UPDATE, June 28, 2017: BCD Travel's Advito slightly raised several of its 2017 airfare projections, owing to strong global demand and improving economic conditions. It also increased to $52 per barrel from $50 its assumption for the price of oil, due to geopolitical tension. "Efforts by airlines to push up prices have so far had only limited success," Advito reported. "But fares may soon start to slowly trend upwards." For North America, the consultancy now expects intercontinental economy fares to rise on average this year by 1 percent versus 2016. It previously forecast no change. It . . .