Russia's Transaero has firmed its preliminary agreement for four Airbus A380s and has also signed an order for up to 16 Sukhoi Superjets.
Transaero signed the deals at an international economics forum in St Petersburg.
The Moscow-based carrier had tentatively agreed to take the A380s - which will be configured for around 700 passengers, in three classes - in October last year.
Transaero has not disclosed an engine selection for the aircraft, for which Russia's VEB Leasing will provide financing.
The deal takes total A380 orders to 257 from 20 customers.
"I am sure that the operation of the A380 will stimulate the development of Russia's aviation sector, in particular, its ground infrastructure," says Transaero chief Olga Pleshakova.
Transaero is also ordering six Superjet 100s, to be fitted with 90 seats, and has placed options for another 10 of the regional type.
Deliveries of the twinjets will begin in 2015 and continue through to 2017.
Transaero values the firm part of the Superjet order at $212 million and says the overall package could amount to over $566 million if all options are exercised.
Each of the Superjets will be fitted with eight business-class and 82 economy-class seats.
Pleshakova says the carrier "deems it to be its duty" to support the Russian aircraft industry, and this depends on firm orders. The airline says the Superjet is "competitive" with similar foreign aircraft.
"Those [Superjets], after being added to our fleet, will take part in realisation of a very ambitious challenge which Russian civil aviation faces - the development of affordable regional air transportation," Pleshakova adds.