President Volodymyr Zelenskiy urged Britain and others on Wednesday to give Ukraine "wings for freedom" by sending combat aircraft to help turn the tide against Russia's offensive, hoping to overcome Western reluctance to take that step. Western countries have scaled up their pledges of military aid for Ukraine this year with promises of hundreds of tanks and armored vehicles as well as longer-range weapons, but have so far refused to deliver war planes. Britain said it wanted to start training Ukrainian fighter pilots as soon as possible and was investigating which jets London could send, but with a caveat that this was long-term action rather than meeting Kyiv's immediate demands. Zelenskiy praised Britain and the West for the support and the sanctions they had provided so far in an address to lawmakers from across the political spectrum in the Gothic expanse of parliament's Westminster Hall in London. But, offering an air force helmet with the message "we have freedom, give us wings to protect it" to the speaker of the House of Commons, the lower house of parliament, Zelenskiy called on the West to deliver up the fighter jets. "I appeal to you and the world, with simple and yet the most important words - combat aircraft for Ukraine, wings for freedom." Earlier, Britain announced an immediate surge of military deliveries to Ukraine to help it fend off an intensifying Russian offensive and pledged to train its pilots to be able to fly "sophisticated NATO-standard fighter jets in the future". But a spokesperson for Prime Minister Rishi Sunak told reporters no decision had been taken on supplying Ukraine with combat aircraft. "The prime minister has tasked the defense secretary with investigating what jets we might be able to give, but to be clear this is a long-term solution, rather than a short-term capability which is what Ukraine needs most now." First stop London was Zelenskiy's first stop on only his second trip abroad since Russia invaded Ukraine on Feb. 24 last year, after a visit to Washington in December. He was expected in Paris later on Wednesday and then Brussels. Zelenskiy also met King Charles at Buckingham Palace, just minutes after he referenced the fact Charles had trained as a fighter pilot, to describe all Ukrainian pilots as "kings". "We've all been worried about you and thinking about your country for so long, I can't tell you," Charles said. In a whistle-stop tour, Zelenskiy was greeted by Sunak at the airport before he entered the Number 10 Downing Street office to applause from onlookers and staff. "I am proud that today we will expand that training from soldiers to marines and fighter jet pilots, ensuring Ukraine has a military able to defend its interests well into the future," Sunak said. Russia is bringing tens of thousands of recently mobilized troops to the battlefield to try to break through Ukrainian defenses in eastern Ukraine in what it calls a special military operation launched to stop Ukraine's shift towards the West. Ukraine's allies have sent tanks and armored vehicles but said it will take time to train Ukrainian forces to use them. Britain has trained 10,000 Ukrainian troops brought to battle readiness in the last six months and will train a further 20,000 soldiers this year, the government said. Last week, Ukrainian troops arrived in Britain to learn how to command Challenger 2 tanks and Sunak will offer to provide Ukraine with longer-range capabilities, a statement from his office said. The move to train pilots was likely to involve simulators rather than advanced Western aircraft and did not mean Britain would soon supply such jets, Justin Bronk, an expert at the RUSI think tank, said on Twitter. But it would help pilots prepare for possible future such deliveries, he wrote.