Washington is sending tanks to Ukraine. Are fighter jets next? Ukraine sure hopes so. The New York Times reports that Ukraine officials have “begun pressing NATO countries on the question of warplanes” to aid its nearly year-long efforts to repel Russian invaders. “If we get them the advantages on the battlefield will be just immense,” says Yuriy Sak, who advises the Ukraine defense minister. President Biden has indicated the U.S. won’t send jets to Ukraine — but some observers note that Western nations were once reluctant to send tanks and even rocket launchers as well, only to eventually relent. Will Ukraine’s latest request follow that pattern? Why does it want jets, anyway? Here’s everything you need to know:

Why does Ukraine want NATO fighter jets?

Ukraine has been asking for Western fighter jets since the beginning of the war. The Associated Press reported shortly after the Russian invasion that Ukraine’s air force uses aging Soviet-made fighters which are “far outnumbered by the much more powerful Russian air force.” Despite that, Ukraine pilots and air defenses have seemingly held their own against the Russians. “Russia’s air power has proved underwhelming,” the University of Texas’ Jaganath Sankaran writes at Lawfare. The Ukrainian air force “trained its pilots to fly their fighters low and exploit terrain to avoid radar detection” and its maintenance crews to fix fighters under grueling conditions.

Still, Ukrainians want more weaponry — including American-made F-16 and F-15 fighters, but also advanced fighters from European countries  — to replace its old Soviet-era jets. Analysts say Ukraine is running out of air defense missiles, Politico reports, and  “modern fighter jets could be one solution to this problem.” F-16s carry air-to-air missiles that can shoot down other missiles and drones that have done so much damage to Ukraine’s electrical grid. 

Why is the U.S. reluctant to send jets?

President Biden, asked this week if the U.S. would send jets to Ukraine, replied with a simple “no.” Biden wants to help Ukraine, the Chicago Council on Global Affairs’ Ivo Daalder tells CBS News, but he also wants to accomplish that mission in a way that “does not risk a direct military confrontation between the United States and Russia, between NATO and Russia.” The F-16 fighters offer Ukraine the ability to strike deep into Russian territory — and for Biden that is “at least up to now a bridge too far.” Finding the balance between assisting Ukraine while not triggering a wider war with nuclear-armed Russia has been Biden’s priority since the beginning of the war. “We will not fight the third World War in Ukraine,” he said in March 2022. But Politico quotes one unidentified American military official pointing out that F-16s were developed in the 1980s, and don’t represent the latest U.S. technology like F-22s or F-35s. “Let’s face it, a nuclear war isn’t going to happen over F-16s,” the official said.

What are other Western allies saying?

There are mixed feelings across Europe. German Chancellor Olaf Scholz has flatly rejected the possibility of sending jets to Ukraine, saying he doesn’t want to encourage a “competition to outbid each other when it comes to weapons systems.” Britain sounds reluctant, but for logistical reasons. “The UK’s … fighter jets are extremely sophisticated and take months to learn how to fly,” a government spokesman told reporters this week. “Given that, we believe it is not practical to send those jets into Ukraine.” But Polish and French leaders have sounded amenable to the possibility. 

What difference would U.S. jets make for Ukraine?

It’s hard to tell. Military observers say adding F-16s to Ukraine’s air fleet would be no “magic bullet” in the war against Russia, CNN reports. The planes would be “a mostly defensive weapon for the Ukrainian military.” And while the Russian military’s shortcomings have been exposed by the war, Russia still possesses powerful air defense systems of its own that might curb whatever advantages American jets offer Ukraine. “Both Ukraine and Russia’s significant anti-air defenses mean that, almost a year into the war, neither country has gained air superiority.” It’s not clear that new fighters would break the stalemate in the air.

What’s next?

Probably a long process. Politico EU reports that “the West will first want to exhaust all other options for air support, including more attack drones and possibly long-range missiles” before sending fighter jets to Ukraine. But there seems to be a widespread belief the pattern the West practiced on tanks — initial reluctance, followed by eventually agreeing to Ukraine’s requests — will replicate itself with jet fighters. “Since we took on the battle over getting tanks to Ukraine, people are understandably asking what will be the next capability,” British Defense Minister Ben Wallace said this week. “What we know about all these demands is that the initial response is no, but the eventual response is yes.”