Luxembourg's flag-carrier, Luxair, is ordering another Bombardier Q400 bringing the airline's total to seven.
It has also taken an option on an eighth of the turboprop type. But the carrier's fleet will stay at 16 because it intends to sell one of its Embraer ERJ-145s shortly.
Luxair disclosed the agreement during the European Regions Airline Association annual meeting in Salzburg.
It says the seventh aircraft will be delivered in spring 2014.
"This turboprop [aircraft] has given us outstanding operational flexibility and performance. At the same time, it has enhanced comfort and convenience for passengers,” says Luxair Group chief Adrien Ney.
Luxair says the 76-seat Q400 will allow it to expand capacity on links to Geneva, Copenhagen and Milan, and open new routes such as Dublin.