Southwest Florida's snowbird crowd rarely realizes that a genuine premium routing exists out of their own regional airport, but booking business class from Fort Myers to Bristol simply requires accepting that RSW has no widebody service and the real journey begins at a US gateway. There is no nonstop option here—no carrier flies RSW to BRS directly—so the practical answer is a connection through Atlanta on Delta, through Chicago or Dulles on United, or through Charlotte or Philadelphia on American, followed by a transatlantic hop into a UK hub (typically London Heathrow or Manchester) with a final short connector into Bristol, since none of these three US carriers operate their own widebody metal directly into BRS. Total elapsed time from Southwest Florida to the West Country usually runs well beyond the raw ~8-hour transatlantic segment once you factor in the domestic leg and UK connection.
Having routed this corridor repeatedly, I favor Delta's Atlanta connection paired with a transatlantic flight in Delta One, whose reverse-herringbone suites with sliding privacy doors on the 767 and A330 fleet make the long eastbound overnight genuinely restful. American's option through Philadelphia into Heathrow puts you in their Flagship Suite on the 777-300ER or A321XLR-adjacent widebodies, with fully enclosed seats that rival anything in the sky, while United's Polaris product out of Newark or Dulles offers similarly private suites with direct aisle access. My insider tip: build in a two-hour buffer in Atlanta, Philadelphia, or Newark rather than a tight connection, because RSW's limited morning departure bank means afternoon US-to-UK connections are often smoother than red-eye scrambles, and a missed transatlantic segment on this itinerary can strand you overnight far from Bristol.
Shoulder-season months—January through March and October into November—consistently produce the softest business class fares on this North America–Europe pairing, as both leisure and corporate demand dip before summer's Cotswolds and Bath tourism surge. Given the multi-carrier, multi-connection complexity of this route, setting up automated fare alerts is the smartest way to catch the fleeting windows when award space or discounted fares align across all three legs.