Battle tanks have been secured from nations including the UK, the US and Germany for the spring offensive in Ukraine, and now Kyiv is looking to the skies and focusing its efforts on acquiring Western-made fighter planes.
Ukraine has been pushing its allies to send advanced warplanes for Ukrainian pilots to help Kyiv take control of its airspace in its ongoing war with Russia.
President Emmanuel Macron has said France does not exclude sending fighter jets to Ukraine if certain conditions are met, while US President Joe Biden ruled out sending F-16 fighter jets during a press briefing, despite renewed calls from Kyiv for more air support. Germany is also reported to have ruled out sending jets.
- F-16s v Russian fighter jets: Comparing air power as Ukraine seeks new jets after supply of tanks
- Ukrainians arrive in UK to begin training on British Challenger 2 tanks
- Vladimir Putin threatened to kill me 'with a missile', Boris Johnson says
However, the Dutch cabinet is said to be considering supplying F-16s, according to the country's media.
Forces News spoke to former Air Marshal Greg Bagwell about whether it is feasible for Ukraine to receive F-16 fighter jets from the West and how these jets might be used by Ukrainian pilots.
Why might the West hand F-16 fighter jets to Ukraine?
According to Mr Bagwell, the F-16 is a "mature aircraft" and is being replaced by various Western countries.
"But it is still a very capable aircraft, plenty of flying hours still on them," said Mr Bagwell.
While there may not be a surplus of the aircraft, according to the retired air marshal, the F-16s are on "their way out of service", which is why they may become more readily available for Ukraine.
The F-16 is a fighter jet with excellent manoeuvrability, versatility, and a top speed of more than 1,200mph.
According to the US Department of Defense, it can spot targets in all types of weather and find low-flying aircraft among radar ground clutter.
The F-16 can fly more than 500 miles in air-to-surface missions.
According to Mr Bagwell, the F-16 is a modern aircraft, with its avionics and radar system having received multiple upgrades over the years.
"It's got all the bells and whistles of all the modern aircraft.
"There are huge numbers of them out there. They are in operations with multiple nations who are already donors.
"It's a bit like the Leopard 2 scenario. You can't get one nation to give them all, so might get five or six nations to give a smaller number," Mr Bagwell added.
How would the F-16 be used?
The former air marshal doesn't see F-16s "being put too far into harm's way", but says they are "part of a layer of defence".
"They would play a key part defending the majority of Ukraine, but wouldn't necessarily be seen flying over the top of the tanks over the battlefront."
The F-16's missiles have a relatively long range, he says, so they don't have to put themselves in harm's way.
Does flying low to avoid enemy radar limit an F-16's capabilities?
"The F-16 is more than capable of operating at low level.It's got a modern radar that doesn't get cluttered by flying low.
"It obviously takes additional skill to do that because of the sheer proximity to the ground," Mr Bagwell says, "but it is a way of maintaining a lower radar signature or lower detection range."
The problem with this, he adds, is that puts the F-16 in the range of shorter-range systems.
He adds: "Nowhere is necessarily 100% safe but, actually, because the weapons now have got relatively good ranges, the radars can detect relatively long ranges, you don't need to get that close to have an effect."
Can arming F-16s with HARM air-to-surface missiles render Russian air defences useless?
Using missiles that target surface-to-air defences is a highly effective way, Mr Bagwell continues.
"Just the very threat of that being there causes a challenge for the enemy", meaning the Russians are reluctant to turn on their radar for long periods of time because "you then become the target yourself".
He says "it's about putting the opposition on the back foot, degrading their ability to be effective".
How do weapons systems on F-16s compare with those on an F-35 or Typhoon?
The weapons systems, ranges and capabilities of the F-16s, F-35s and Typhoons are very similar, although the older F-16 doesn't have "quite the same stealth characteristics".
What are the challenges of training Ukrainian pilots?
Mr Bagwell says a lot of people assume it takes years to get people capable of operating a complex system like a fighter jet.
"And if you're a young pilot just starting at the age of 19 there's some truth in that," but, he says, for a combat pilot with hundreds of hours of flying experience, "I believe you can take an experienced pilot in about six to eight weeks and convert them across".
But for a country at war with Russia, "health and safety and some of the regulations that we apply in peacetime, clearly, will not apply".