Some F-16s are arriving in Ukraine, so what does it mean for war with Russia?
Small number of fighter jets and required training for pilots factor into how useful planes can be
Ukraine has received a first batch of U.S.-built F-16 fighter jets to help it fight Russian invasion forces, Lithuania's foreign minister and a U.S. official have said.
The long-awaited arrival is a milestone for Ukraine, which has not publicly commented on it for now. The lengthy process to procure the U.S.-designed aircraft and train Ukrainian pilots to fly them has frustrated Kyiv.
Russia has had time to prepare defences to try to nullify the impact of the F-16s, and Ukraine has had to survive with a depleted air force a fraction of the size and sophistication of its enemy's.
Here are some facts about how the F-16s may help Ukraine and what obstacles still stand in the way of effective deployment.
Few delivered so far
The number of delivered F-16s appears to be small for now. The Times of London put the figure at just six planes, citing a source familiar with the matter.
That number is expected to grow, but it is far short of what military analysts suggest Ukraine needs more than 29 months since Russia launched its full-scale invasion.
Serhii Kuzan, chairman of the Ukrainian Security and Cooperation Center, a non-governmental research group, said at least 60 planes would be needed for significant operations as Ukraine attempts to push Russian aviation back from its borders.
Lawmaker Oleksandra Ustinova, who heads Kyiv's parliamentary commission on arms and munitions, said Ukraine would need closer to 120 F-16s to boost its air capability significantly.
While the pilots gain experience in Ukrainian skies and the military builds its air infrastructure, the initial deliveries could at least help Ukraine strengthen its air shield, some experts say.
"It will provide some air defence and depth capacity, potentially also help intercepting Shaheds (Iranian-built drones) and cruise missiles, although it is a very expensive way of doing that, munitions-wise," said Justin Bronk, senior research fellow for air power and technology at the Royal United Services Institute (RUSI).
Much hinges on availability of missiles
Valeriy Romanenko, an aviation expert, said the jets would likely help Ukraine better launch air-to-surface missiles, which it already possesses. He said much would hinge on what new missiles Ukraine is given with the warplanes.
"If we receive the 95-kilometre range [missiles], F-16s will only engage in air defence tasks and chase Russian attack aircraft or helicopters in the south," he said.
Receiving missiles with 180-kilometre range would allow them to attack Russian warplanes armed with guided bombs and help significantly reduce Russia's offensive opportunities.
Ukraine's military has worked hard to reduce the threat to the arriving F-16s in recent months by attacking Russian air defences, according to Kuzan.
"The formation of the battlefield, especially in the south, is already taking place. Ukraine has the capabilities to systematically strike Russia's foremost air defence complexes."
Getting pilots ready
Training will be crucial.
"You can have lots of fast jets, but if they don't have effective weapons, and air crew able to employ them with effective tactics, then they will just be shot down in large numbers," said RUSI's Bronk.
The timeline for the training of Ukrainian pilots on F-16s has dominated discussions about deliveries and pledges of more than 70 jets.
By the end of 2024, Ukraine expects to have at least 20 pilots ready to fly F-16s, Ustinova said.
"It is difficult to solicit more planes when you don't have people to pilot them," she said, noting that, at first, Ukraine will have more F-16s than qualified pilots.
"Waiting in line for 10 years before our pilots are trained is not OK."
A spokesperson for the Ukrainian Air Force declined to comment.
U.S. officials have directed questions on training to Ukraine and noted that pilots can also be trained in Europe. However, Bronk says NATO's capacity was already stretched.
He also notes that aircraft maintenance is an even more pressing challenge than pilot training, saying most repairs and maintenance would need to happen inside Ukraine, and that Kyiv would probably have to rely on foreign contractors who know the aircraft.
Air bases under threat
Russia has intensified its attacks on infrastructure that could be used for the maintenance and deployment of F-16s, according to some experts.
"Russia is striking all airfields, potential F-16 bases, every day, including attempts to damage airstrips and infrastructure. These strikes have not paused for the last two months, at least," Kuzan said.
The targets will become all the more valuable when the aircraft, pilots and maintenance teams arrive. This is likely to force Ukraine to install missile defences to protect them, even though it is short of both air-defence systems and ammunition.
"We have to accept the fact that the airfields will be well-protected when civilian objects could be under attack," Kuzan said, adding that each base would need at least two Patriot and two NASAMS batteries to secure it.
He said that as soon as Ukraine builds up its flight capabilities, "we will push their planes back and the terror will stop. But these couple of months will be truly difficult."