From my post above, the explanation you need. Pls read, then you may understand
"The Westray-Papa Westray flight is not operated in isolation, it is part of a "round robin" schedule and that sector flies over the very rough arm of the North Sound between these two Orkney Islands.
I don't think there are (m)any pax just travelling between the two points in isolation. Both islands are reasonably remote and have their own populations who are dependant on the mainland and the larger Orkney Islands for supplies and their livelihoods."
As for a bridge, there may be a few tractors on the islands but hardly any cars, so what would be the point of spending millions in a very remote and wild area?
This is aviation at its best, providing a social service.
I don't think that there are any special protection measures, just regular washes. Flights to Barra have been taking place since the 1930s. DH Dragon Rapides were followed by DH Heron 1s in the 1950s and 1960s
and when BEA became BA Short 330s were used. These were followed by DH6s of Loganair who won the contract and now operate the route as a BA partner.