Delta Air Lines’ efforts to expand its US-to-Africa service, filling a void in air travel left by Pan American World Airways’ demise almost two decades ago, hit a snag this week after US officials blocked the carrier’s planned routes to Kenya and Liberia.

The setback came a day before passengers were set to board Delta’s first flight from Atlanta to Nairobi, the Kenyan capital, via Dakar, and underscored the challenges air travel and tourism officials on both continents face in seeking to capitalise on the growth of developing economies throughout Africa.