OTTAWA -- Canada's head of military procurement says the federal government is facing a short runway if it wants to get new fighter jets in time to avoid putting even more money into its aging CF-18s.

Patrick Finn, the Defence Department's assistant deputy minister of materiel, says officials are working overtime to launch the $19-billion competition to select Canada's new fighters next month.

Yet while the government has said it wants to identify a winner by 2022 and get the first new aircraft in 2025, the Defence Department is now acknowledging that schedule is very aggressive.

Finn says officials won't have a real handle on when the first new fighters can be delivered until the winning company is picked and the two sides can hammer out the details.

Yet he also admits the government is facing a time crunch: a delay could result in the need to invest more money in the CF-18 fleet, which is nearly 40 years old.

The CF-18s were originally supposed to have been retired in 2003 but have undergone several rounds of upgrades and defence officials are wrestling with how long and how many to keep in the air.