Minuscule to a vanishing point, I suspect,
NWIFlyer
I have no personal desire to punish BA financially ... the greater Public may do that (or not). I just want cheaper J fares and a better cabin environment, which AAnother AAirline provides when heading West from DUB
PS: Just pre-ordered our return meals, PHL-DUB. Cajun Duck Breast. Hmmm - should be interesting