Problem was that the aircraft couldn't make it back to the US on a single tank of fuel if the jet stream was too strong. Which happened a lot. So we got a nice detour to Goose Bay for refueling and nearly missed our connection. The regulars joked that YYR was the new United hub on the east coast.
I don't think UA does this much anymore. Maybe COVID killed that route too.
check out how they compare here: https://www.aviatorjoe.net/go/compare/737_MAX_10/757-200/
the 757 was the best narrow-body long-haul capable jet of the time (and it was the only one of its type that could fly LGA) but more fuel-efficient engines will do to it what the 787 did to the 747.
An erroneous ; was added. Probably not LLM.