Jamie Dettmer is opinion editor at POLITICO Europe.

Ukrainians are reacting with frustration, and in some cases fury, to reports that it could take until next summer — and possibly longer — to complete the training of Ukrainian pilots, so they can proficiently fly their much coveted F-16 warplanes.

The F-16 is a versatile fighter, and one that President Volodymyr Zelenskyy has been pleading for since the very early days of the Russian invasion. On Friday, the Netherlands and Denmark confirmed they had received approval from the U.S. to hand over F-16s to Ukraine as soon as pilot training is complete. 

That question of pilot readiness is extremely contentious, however.

United States Air Force General James Hecker, the commander of U.S. Air Forces in Europe and Africa, told reporters that getting F-16 squadrons ready for battle could take “four or five years.”

Admittedly, Hecker was talking about top expertise, but even for basic capability — such as solo air-to-ground attacks — six months will likely still be needed. And there’s no way around it either.

“This is unfair and a scandal,” wrote Tymofiy Mylovanov, an adviser to the Zelenskyy administration and head of the Kyiv School of Economics. Mylovanov and others identify a familiar pattern of foot-dragging here, arguing there’s a lack of urgency on the part of Western allies, and too much adherence to hidebound bureaucracy.

They point to an American Air Force assessment of two Ukrainian pilots carried out last February, which suggested that four months would be a “realistic training timeline.”

Neither of the pilots had any previous experience with the F-16, and they were tested on a simulator at Luke Air Force base in Arizona — the pre-eminent American F-16 training center. But according to the report, during nine sessions of almost 12 hours each, they were both able to conduct several “relatively technical” maneuvers, including landing and accomplishing “mock attacks based on parameters communicated while they were flying the sim.”

The assessment was shared with NATO allies.

Ukrainian Minister of Defense Oleksii Reznikov also cited this assessment in his claim that training will take no time at all. He invoked Ukrainian exceptionalism, arguing his pilots are quick learners and will be able to master the warplane much faster than the standard six months for basic capability. “I believe that because we know how to surprise people. That’s what we’re actually like — we know how to learn,” he told Current Time TV in June.

As evidence, Reznikov pointed to how Ukrainian crews learned to use the howitzer Caesar systems in just three weeks instead of the standard three months. “The French and the Poles were delighted! Because they didn’t just take and finish the course, they actually completed all the tasks that are assigned to a team training for three months,” he said. And he has boasted of Ukrainians’ speedy mastery of Western-supplied Patriot air defense systems too.

His adviser, Yuriy Sak, has also been equally bullish.

When the administration of U.S. President Joe Biden finally relented and agreed F-16s could be transferred to Ukraine by third countries, Sak noted that if training got underway quickly, F-16s could be flying in Ukrainian skies within a handful of months. “If we all pull our weight . . . and decisions are made quickly, I would estimate that end of September, early October, we could see the first F-16s flying in Ukrainian airspace,” he said.

Now, however, he’s talking about January, and that’s if teething problems and training wrinkles can be ironed out, and if the Europeans offer enough F-16 instructors — a real challenge, as many air forces are in the middle of transitioning to the advanced F-35. Understanding the instructors is also a problem, with 20 of the Ukrainian trainees needing blitz English courses in the U.K.

All this has been fueling suspicions among some Ukrainians that the long timelines mentioned by some Western officials are a made-up excuse — all part of erring on the side of caution when it comes to giving Ukraine modern weapons systems, stemming from fears of the war widening and Russia retaliating beyond Ukraine.

But the different estimates for the time necessary to train F-16 pilots and the challenges they will face don’t fit into the familiar pattern of delay — though the belated decision to agree on sending F-16s clearly did. There are limits even to Ukrainian exceptionalism, experienced F-16 instructors and pilots told POLITICO. According to them, a needs-must approach just won’t cut it, and proficiency will take much longer to achieve than just relying on Ukrainian ingenuity — quick learners or not.

They also add that training novice pilots from scratch and transitioning pilots who are experienced on other warplanes are both time-consuming and present different challenges — it just isn’t like “jumping from a Mini to taking the wheel of an F-150 Ford truck,” says a current US F-16 pilot, who asked not be named as he isn’t authorised to talk with the media.

“You’ve seen the latest ‘Top Gun’ movie where Tom Cruise says, ‘If you think, you die,’” said Tom Richter, a former US Marine F/A-18 Hornet pilot who later transitioned to the F-16. “As Hollywood-cheesy as that might be, it is true.”

Now a commercial pilot, Richter, nicknamed T-Bone, tried to explain switchology: “If you’re thinking, ‘Where’s the switch, how do I employ my weapons?’ — there’s a problem. It has to be natural and intuitive, and that only comes with experience.” For pilots transitioning from other aircraft that’s especially awkward. “You become so comfortable in certain aircraft that you do things without thinking as you should, and with experienced pilots, you must basically retrain them to be intuitive, to forget their muscle memory and become intuitive on the new system,” he added.

“Let’s assume the pilot is familiar with the MiG-29. It’s an aircraft that is designed completely differently. The avionics, information and weapons systems they employ are completely different. So, you’re taking a pilot and telling him he has to relearn everything he has assimilated before, and has to develop an entirely new muscle memory, so that up in the skies, he doesn’t have to think. In some ways it is probably easier to take someone cold off the street and teach them,” he explained.

Inexperienced or not, Richter estimates it will take at least to six to seven months to get a pilot up to basic combat standards — and that’s when everything is proceeding smoothly, including no bad weather or aircraft breakdowns disrupting flying hours or trainees encountering hiccups.

Then, when basic training has been concluded, he said, ideally there should be another three months focused on training for air-to-air combat, and then another three months for air-to-ground attack. “Then you will be introduced into your permanent formation and train as a wingman, and we’re really going to add scenarios because you basically just kind of learned the basics up until now, and we want you at full combat quality,” he explained.

There can be shortcuts, of course, and pilots could be thrown into combat much earlier after basic training, as there won’t be any established F-16 formations to join. “They’re basically going to be thrown right into the fire,” Richter said — and with considerable risks too, as the skies above Ukraine are highly contested, with sophisticated air defense and electronic warfare systems deployed.

And, not to forget, Russia has its own experienced pilots as well.