President Volodymyr Zelenskiy renewed his appeal on Wednesday for U.S.-built F-16 fighter jets, saying their appearance with Ukrainian pilots would be a sure signal from the world that Russia's invasion would end in defeat.
"The main thing is the speed in training and in supply - meaning the time between decisions in real protection for our skies," said Zelenskiy, whose air force uses Soviet-era jets.
The following are some facts about an alliance forming in what Zelenskiy proposed as a "jets coalition" of Western backers to provide the aircraft and the training to combat Russian air attacks:
WHO IS COMMITTED TO 'JETS COALITION'?
The idea received a big boost last week when senior U.S. officials said President Joe Biden told G7 leaders that Washington supported joint allied training programmes for Ukrainian pilots on F-16 fighters.
But U.S. National Security adviser Jake Sullivan said there was no final decision on Washington sending aircraft.
German Chancellor Olaf Scholz, also speaking at the G7 summit in Hiroshima, said the training pledge was a message: "Russia cannot count on winning if it bets on a long war."
On Wednesday, Norway's defence minister said his country supported joint training programmes but had yet to decide on aircraft. The Dutch defence minister offered similar support.
NATO chief Jens Stoltenberg said on Tuesday that training Ukrainian pilots would not make NATO a party to the conflict - the U.S.-led military alliance ruled out a "no fly" zone from the very start of the war 15 months ago, to avoid any notion of direct conflict with Russia.
The transfer of F-16 jets to Ukraine would raise the question of NATO's role in the conflict, senior Russian diplomats said on Monday. "There is no infrastructure for the operation of the F-16 in Ukraine and the needed number of pilots and maintenance personnel is not there either," said Russia's ambassador to the United States Anatoly Antonov.
U.S. officials have estimated that at least 18 months will be needed for training - in Europe - and delivery of F-16s.
Zelenskiy has won pledges from British Prime Minister Rishi Sunak and Dutch PM Mark Rutte. Neither man has committed to sending planes.
Western governments have been wary of leaving their own countries undefended by giving away too much equipment. They have also avoided sending anything that could strike deep into Russian territory and give Moscow a reason to broaden the war.
Any coalition of donors of the F-16, built by Lockheed-Martin, would likely be reliant on backing from the United States, by far the largest operator of the planes.
No Western-designed jets have been donated. Poland and Slovakia have supplied 27 MiG-29s to supplement Ukraine's fleet.
Poland has given Ukraine 14 MiG-29s and said it will give more. However, Polish President Andrzej Duda has said Warsaw has too few F-16s to give any to Ukraine.
Slovakia has donated 13 Mig-29s in various states of airworthiness to Ukraine.
WHERE MIGHT THE JETS COME FROM?
Rutte said on May 4 that the Netherlands was working with allies including Britain, Belgium and Denmark to reach a conclusion on whether to send jets to Ukraine.
The Netherlands has 24 F-16s operational until mid-2024, when they will be replaced by F-35s. It has also 18 F-16s non-operational, of which 12 have been sold.
Britain will not send jets to Ukraine, a spokesperson for Sunak said, since Britain does not have the F-16s Ukraine wants. Britain was ready to back any country willing to send jets, Sunak said.
Germany said it does not own any F-16s, but Defence Minister Boris Pistorius said it was looking into options to support a coalition of countries to train Ukrainian pilots.
Denmark, with about 30 F-16s in operation, said in February it was "open" to the idea of sending fighter jets to Ukraine.
An alternative could be the JAS Gripen produced by Swedish defence manufacturer SAAB (SAABb.ST), which is seen as more cost effective.
Sweden, which has applied for NATO membership, has said there are no plans to send Gripens to Ukraine and that it needs its existing inventory. The Czech Republic uses rented Gripens while Slovakia is waiting to receive F-16s.
WHEN CAN TRAINING START?
President Emmanuel Macron said this month that France was open to training Ukrainian pilots in France right away. France does not have F-16s, only French-made Rafale warplanes and the previous generation Mirage 2000 jets.
Britain has agreed to start training in the spring and said it will consider shortening sessions.
