United hopes to begin flying between Washington and Cape Town from November but will face competition for the available weekly frequencies under the US-South Africa air services agreement.
France’s flag-carrier is opening a second route to the UK capital this summer and has received the green light to begin codesharing with Italy’s ITA on transatlantic routes to the US.
A total of 13 routes are being launched from the secondary airports in Chicago and Houston by Frontier, most of which are served by rival Southwest Airlines.