BHX2FRA
Both WW flights do well with a fair few suits on board, the regional flight time do allow you to attend a meeting and get back home without an overnight stop which goes some way to offset the extra cost. The early start East bound will not get you into FRA to pick up first wave departures so a lot depends on where you connecting onto.
Early morning winter fog could be a problem into FRA the Embraer is only cat2 so needs 300m RVR