United is embarking on the largest transatlantic expansion in its history, which it said comes in anticipation of a "strong recovery" in European summer travel.
It will launch or restart 30 transatlantic flights from mid-April through to early June, and restart another 14 Atlantic routes it has historically served.
Overall, United plans to increase its transatlantic route network by more than a quarter compared with 2019.
"We have long anticipated a strong demand recovery, evidenced by our large, strategic expansion in Europe," said Patrick Quayle, United’s senior vice-president of international network and alliances.
From 14 April, United introduced new daily flights between Boston and Heathrow, alongside existing non-stop Heathrow services from all seven of its hubs.
There are also new daily flights between Denver and Munich and Chicago and Zurich, and from 29 April, New York Newark and Nice. New daily flights between Chicago and Milan will get under way on 6 May.
Frequency increases include second daily flights between New York Newark and Dublin (effective from 23 April), Denver and Heathrow (7 May), New York Newark and Frankfurt (26 May) and New York Newark and Rome (27 May).
United is also adding a third daily flight between San Francisco and Heathrow and increasing its service between New York Newark and Heathrow to seven-times-daily, beginning 28 May.
This will increase its US-UK schedule to 22 daily non-stop flights to Heathrow.
