United Airlines is about to put some surprisingly long flights on surprisingly small planes. From March 28, 2027, the Star Alliance carrier will launch two transcontinental routes out of San Francisco International that both stretch past the six-hour mark on narrowbody Boeing 737s — and one of them is a brand-new market for the airline.

The fresh link is SFO to Charleston, South Carolina, served four times a week (Mondays, Thursdays, Fridays and Sundays) on a 166-seat 737 MAX 8. United has never flown the pair before. The eastbound leg leaves San Francisco at 8:10 AM and arrives at 4:35 PM after 5 hours 25 minutes; the return departs at 5:40 PM and lands at 8:50 PM after 6 hours 10 minutes in the air. At roughly 2,082 nautical miles, it becomes Charleston's second-longest nonstop, behind only Alaska's Seattle service.

The route has history, though not United's. Breeze Airways tried San Francisco–Charleston starting May 2022 — its second-ever transcontinental route — but dropped it after less than a year, in January 2023. Load factors hit a respectable 76%, but apparently the fares couldn't cover it. There's still real demand: US DOT data shows about 59,200 round-trip passengers a year connecting indirectly between the two cities, making Charleston SFO's third-largest unserved domestic market. United's timings also set up tidy connections to its big Asia-Pacific bank at SFO.

The second route is a comeback. SFO to Hartford, Connecticut's Bradley International Airport returns the same day, this time daily on a 179-seat 737 MAX 9. United flew it from 1997 to 2001 and again in 2017–18; JetBlue gave it a shot from December 2020 to April 2022, and it's been dark ever since. At 2,281 nautical miles, it will be Bradley's longest domestic nonstop, edging out Las Vegas. Schedule: a 12:15 PM departure from San Francisco arriving 8:52 PM, and a 6:20 PM return getting in at 9:40 PM. The local market is bigger too — about 82,400 annual round-trip passengers, with Hartford ranking as SFO's second-largest unserved domestic market after Los Angeles.

United isn't stopping there. It's also adding Chicago O'Hare to Bermuda — a route it last flew in 2007 — plus SFO to Oklahoma City, which returns after a 2020 exit.

Why should travellers care? These are point-to-point options where you'd previously have connected through Denver, Chicago or Dallas, shaving hours off the trip. The westbound evening departures and morning eastbound arrivals also make sensible schedules for a week away — you land in Charleston or Hartford with the evening ahead of you, and the return gets you home at a civilised hour. Bookings open well ahead of the March 2027 start, so there's time to watch for launch fares, which on revived routes like these are often competitive in the first months.