Why does British Airways want to charge £652 for switching one domestic flight?

Hebridean express: path of British Airways flight 219 over Scotland's Western Isles - (Flightradar24)

Many transatlantic flights overfly the Outer Hebrides; my British Airways flight last week from London to Denver did just that. But for the residents of Scotland’s wonderful Western Isles, reaching America proves a palaver.

Dolina MacLeod and her husband face a long journey in October when they travel from the Outer Hebrides to visit their daughter in New York. “We booked some time ago on British Airways from Edinburgh to New York via London Heathrow, both ways,” she says. “Since then, flight schedules have updated.”