Originally Posted by Globaliser

EF shows no seats available on LHR-HYD on any day in April 2022. All booking classes are zeroed. So BA has taken this off sale at the present time. The flight has not been formally cancelled, which is why your reservation is still live. But that does not preclude a later cancellation, nor does any of this mean that BA won't put the flight back on sale later.

If by "seats available" you mean that there are seats on the seat map that are not pre-allocated, the seat map tells you absolutely nothing about what BA is prepared to sell at the present time.

In addition, HYD-LHR is not bookable every day in April 2022. There is inventory only on three days a week. This is a possible clue as to what BA is thinking, but as c-w-s says, you will have to wait and see what shakes out. It could be anything from an imminent aircraft change to outright cancellation of the route. At this point, only BA insiders could know (and even BA may not yet have decided what to do).

Although it may be unlikely at this stage as a plan for HYD, it's perfectly possible for BA to sell HYD-LHR but not LHR-HYD. There are plenty of examples at present of airlines carrying passengers in only one direction on a route. So it's theoretically possible for the aircraft to operate LHR-HYD with no passengers, and only carry passengers HYD-LHR. Will BA actually do this? Impossible to say at present.