Next week at the Paris Air Show, the largest aviation gathering of the year, Airbus will undoubtedly announce a lot of airplane orders.

But Boeing is set to steal the show.

The most influential player in the aviation business is working to finalize this weekend a huge order for about 50 Boeing 787 Dreamliners, worth at least $5 billion even with discounts.

The deal will ensure that International Lease Finance Corp. (ILFC), the biggest airplane leasing company in the world, owns more Dreamliners than any other customer. The biggest previous 787 order from a single buyer was All Nippon Airways' 50-plane launch order in 2004.

ILFC founder and CEO Stephen Udvar-Hazy is likely to announce the order Tuesday.

In contrast, Hazy will hold back any commitment to the rival Airbus A350 jet until the European planemaker gives more solid and detailed specifications for the aircraft. Some other big industry players seem likely to do the same.

For Boeing, capping the show with the big, unexpected ILFC order would be a surprise that extends the 787's strong momentum and nicely sets up the rollout of the first Dreamliner in Everett next month. But Airbus could leave Paris still short of a convincing demonstration that its airplane is a solid competitor.

Hazy hinted at his plans in an interview at the annual conference of the world's top airline executives in Vancouver, B.C., last week. Subsequent conversations with two Boeing executives with knowledge of the negotiations established the size and likely timing of the deal.