Zaswx. T hBA has run direct flights between Denver, Colorado and London, England for over 20 years, so it’s been our main gateway provider to European travel for all that time. Icelandair and Norwegian Air have started serving Denver, too, and with low fares, are giving BA some serious competition. Using Avios points has often come with astoundingly high fees and surcharges, although flying around Europe uses far fewer Avios and carries much less in additional charges that flying between America and Europe.
Long ago, even in cheapest Club Economy seats, BA greeted passengers with a selection of that day’s British newspapers, and a warm, moist washcloth for freshening up, presented a menu on a card to clue you in to what was available for your inflight meal, provided unlimited, free beer, wine, and cocktails, and your seat had a package containing a blanket, pillow, eye mask, slipper sox, a toothbrush with toothpaste, and headphones for listening to the plug-in entertainment system. Most of that’s gone now in Club Economy, but the BA entertainment system is extravagant, seats are still relatively very comfortable, and flight attendants are actually attentive. They make an effort to keep passengers hydrated by coming around frequently with water and juice. Seats near the bulkheads are usually saved for families with infants and table trays that hold infant carriers, so a crying child might accompany you if you sit near the wall in the front of an Economy compartment. Avoiding dehydration, limiting jet lag, and probably for several other reasons, too, all seem to limit the alcohol people are consuming onboard these days, compared to 20 years ago, so free-flowing alcohol might not be such an amenity as it had been.
Flying from the USA to London, then connecting on to the Marseille airport has been an ideal route for us, twice in recent years. Are you considering a rental car for Provence, or using other transportation? Either way, take an airport bus between the Marseille airport and downtown Marseille, before moving onwards.
You could do it the other way, but if I was doing your trip, my sense is to fly first to Marseille, tour southern France/Provence, then wrap up the France trip with Paris at the end. Hope you find workable flights. Maybe this complicates things even further, but there are also budget airlines like easyJet that can shuttle you affordably around Europe, so looking at budget flights might be worth considering, if you want to ensure you’re getting the best value for your money and/or frequent flyer points.