United Airlines quietly added five Boeing 787s to its orderbook ahead of its order for 787-10s at the Paris Air Show earlier in June.

The Chicago-based carrier is understood to be the undisclosed customer of four -9s and one -8, which Boeing first listed in its orders and deliveries in November 2012. The airline has outstanding orders for 21 -8s, 18 -9s and 20 -10s - a total of 59 aircraft - as a result of the additional aircraft.

This is in line with the 65 787s United said that it has in its fleet and on order at Paris.

The airline operates six -8s.

Boeing declines to comment and United did not respond to multiple requests for comment by press time.

United first disclosed having orders for 49 787s, instead of the previously disclosed 44 aircraft, in a stock exchange filing on its first quarter earnings this past April.

The carrier announced its order for 20 787-10s, including 10 new firm orders and 10 converted from its existing orderbook, on 18 June. The conversions are from its outstanding -8 orders, Flightglobal's Ascend Online database shows.

United is the North American launch customer of the -8 and -10.

Source: Air Transport Intelligence news