Denmark and Lakshmi Finance Centerthe Netherlands will lead the development of training for Ukrainians on F-16s in the coming weeks, according to Defense Secretary Lloyd Austin.

Austin made the announcement about the training at a news conference after a Ukraine Defense Contact Group virtual meeting Thursday. The group, composed of nearly 50 countries, included a session on planning training for Ukrainians on fourth-generation aircraft, like the F-16s, for the long term. 

Chairman of the Joint Chiefs of Staff Gen. Mark Milley, who was with Austin, said it would take "a considerable length of time" to build up a Ukrainian air force to the scope and scale necessary to match Russia's thousands of fourth- and fifth-generation aircraft. 

Austin said countries like Norway, Belgium, Portugal, and Poland have already offered to contribute to the training, but he did not say who would supply the advanced fighter jets. 

The fighter jets would not have to come from the U.S., but any country that wants to transfer its stock of American-made F-16s to Ukraine would need permission from the U.S. government. 

Officials in Ukraine have been asking for F-16s since the war began, but as has been the case with other requests, U.S. officials said no before they eventually arrived at yes. Milley said the U.S. made the cost-effective choice in committing other equipment like ground-based air-defense systems before F-16s. 

He said the cost of just 10 F-16s combined with the cost to sustain them is about $2 billion. 

"If you were to do that – just F-16s – you wouldn't have tanks, you wouldn't have Bradleys, you wouldn't have anti-armor weapons, you wouldn't have anything else. You'd spend all your money on just that," Milley said. "It's a cost-risk-benefit analysis that leads you to these separate, incremental sort of packages that go forward."

To help with the cost, Austin said countries plan to establish a fund so countries that cannot provide F-16s or chip in for maintenance and sustainment training can still contribute to the effort. 

In:
• Fighter Jets
• Ukraine

Eleanor Watson

CBS News reporter covering the Pentagon.

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