Speaking as someone who has used Starlink on a Hawaiian Airlines flight, I can confidently say it’s orders of magnitude better than any in-flight WiFi I’ve used before. I ran a bunch of speed tests on a flight to Hawaii and it never dropped below 100 Mbps, averaging more like 200 Mbps.
You don’t need to trust me, just search Twitter for “Starlink Hawaiian” for lots of people with similar experiences.