• It was a pivotal moment for Ukraine on Sunday, as President Volodymyr Zelenskyy watched on as two F-16 fighter jets roared overhead.
• Flanked by another two of the U.S.-made combat aircraft at an undisclosed location in Ukraine, Zelenskyy announced that the country's air force had already started operations using the warplanes against Russia.
• The difference they'll make on the battlefield remains to be seen.

It was a pivotal moment for Ukraine as President Volodymyr Zelenskyy watched two F-16 fighter jets roar overhead, after many months of waiting for the combat aircraft that Kyiv hopes will change the dial in the war against Russia.

Flanked by another two of the U.S.-made combat aircraft, Zelenskyy announced on Sunday that the country's air force had already started operations using the warplanes against Russia.

"F-16s are in Ukraine. We did it. I am proud of our guys who are mastering these jets and have already started using them for our country," he said, speaking to military pilots and reporters at an undisclosed location in Ukraine.

"These jets are in our sky and today you see them," Zelenskyy added, thanking Ukraine's allies for the supply during the unveiling ceremony on Ukraine's Air Forces Day. "It's good that they are here and that we can put them to use."

A number of Ukraine's European allies have pledged to send F-16s to Ukraine, and the first batch arrived in the country in late July. It remains uncertain how many of the combat planes were sent to Ukraine.

On Sunday, Zelenskyy did not specify the number of jets that had already been delivered, but said that more were expected. He also conceded that more pilots needed to be trained to use them.

The arrival of the first combat aircraft in Ukraine nonetheless marks a notable achievement — Kyiv repeatedly requested the aircraft from allies over many months of the war. It has awaited U.S. approval for the export of F-16s from allies willing to transfer them to Ukraine, and then the training of Ukrainian pilots to use the aircraft has also taken months.

Denmark, the Netherlands, Belgium and Norway have agreed to send around 80 aircraft to Ukraine, although the timeline for their delivery varies. Most are not expected until 2025.

U.S. secretary of State Antony Blinken said in July that F-16s from Denmark and the Netherlands would be 'in Ukraine's skies this summer.'

Ukraine has lobbied its NATO allies for F-16s since the early days of the the war against Russia, arguing that the jets will enable it to better defend its air space, ground troops and critical infrastructure from Russian attack, as well as to strike enemy targets more effectively.

Russia has dismissed the supply of F-16s, with Kremlin Spokesman Dmitry Peskov saying last Thursday that Russian forces were prepared to shoot down the F-16 jets.

"There is no 'magic pill' here. There is no panacea," he told reporters last Thursday, according to russian state news agency Tasss.

"The armed forces of the Kyiv regime will not get a universal remedy. They should be aware of that. Should these airplanes appear, their number will gradually decrease. They will be shot down and destroyed. These supplies will be unable to have any significant impact on the developments on the frontline," he stated.

Peskov said Russian servicemen had been offered rewards for the destruction of F-16s.

Impact uncertain

Kyiv is understandably tight-lipped about the weaponry that its F-16s will be equipped with, as well as the targets of the aircraft. On Sunday, Zelenskyy suggested missions will be kept secret, saying it would be "dangerous" to comment on how the F-16s will be used.

Defense analysts say it's like they could carry longer-range missiles, giving Ukraine a greater ability to strike Russian forces that are occupying swathes of the south and east of the country.

"The F-16 models that Ukraine has now begun to receive are a clear step up from the Soviet-era jets inherited from the USSR, boasting superior radar capabilities and longer range. At the same time, Ukraine's F-16s should not be viewed as a game-changing weapon in the war with Russia," Mykola Bielieskov, a research fellow at the National Institute for Strategic Studies think tank, said in analysis last week.

"One obvious issue is quantity. Ukraine has so far only received a handful of F-16s, with a total of 24 jets expected to arrive by the end of 2024. To put this number into context, Ukrainian President Volodymyr Zelenskyy has stated in recent weeks that in order to effectively counter Russian air power, his country would require a fleet of 128 F-16 jets," Bielieskov noted.

The fledgling F-16 fleet was also likely to have access to a limited selection of weapons, the analyst said, with the aircraft's effectiveness likely constrained by restrictions on the use of Western weapons against targets inside Russia.

"It remains unclear whether Kyiv can count on longer range strike capabilities, despite recent reports that the U.S. has agreed to arm Ukrainian F-16s with American-made missiles and other advanced weapons," Bielieskov said. He said the jets' initial use would be to strengthen the country's air defenses.

"The jets will considerably enhance Ukraine's ability to prevent Russian pilots entering Ukrainian air space, and can also target Russian cruise missiles in flight. This is particularly important as Russia has recently demonstrated its growing ability to bypass existing surface-to-air defense systems and strike civilian infrastructure targets across Ukraine," he said.

"Ukrainian F-16s will be challenged to independently create conditions for a much-desired breakthrough in the war with Russia," defense analysts at the Center for Strategic and International Studies agreed.

"But with the right strategy, doctrinal approach, logistical support, and training, F-16s could provide a critical advance in enhancing Ukraine's border defense and establishing localized air superiority, significantly bolstering Ukraine's position on the ground," Christopher Koeltzow, Brent Peterson, and Eric Williams noted in analysis.

Ukraine's need for F-16s has become more acute, as the country's air force — which predominantly relies on Soviet-era aircraft — has generally faced a superior enemy in the sky by way of Russia's more advanced Sukhoi fighter-bombers.

As with the delay over whether to supply battle tanks to Ukraine, the decision to provide F-16s has not been straightforward, with Ukraine's international partners wary of escalating tensions with Russia.

Hold-ups over such decisions has caused frustration in Kyiv and has arguably given Russian forces more time and space to slowly advance in the east of the country, after launching a new offensive there earlier in summer.