Honestly, I think any US-Europe route is "high dollar" in the summer months. The problem for most airlines is making these routes work in winter, especially from cities which have enough J class demand to require daily, year-round service but where Y is quite empty and cheap for most of the year.
Absolutely. Between strong partner hubs, and the large widebody fleets that can be moved around seasonally, the trend at the U.S. legacies really seems to be going to summer seasonal for most Europe routes, except those to partner hubs and those to key financial and banking cities like ZRH, FRA, or MXP. Seasonal fluctuation has always been a problem for the industry, though. TW had year round service on 747s to ATH, MAD, and FCO for much of the 1980s, but those flights were often extremely empty in the winter and crazy oversold in the summer. DL probably moves as many people to and from ATH each year as TW did, but they fly the route less than half the time and then 10 times a week in the summer.
The question is how not to annoy elites by routing too much winter traffic through partner hubs - like AA will for all 3 of these new summer seasonal Europe flights. Going to southern Europe in the off season sucks, because you have the awful 6am connection through the partner hub, and then the extremely early departure on the way home to make the mid-morning partner hub connection. I always try to wait to go to europe until at least March when some of the shoulder season non stops come back - because the schedules are so much more convenient.
I think there is an obvious trend in those routes, and other new TATL routes such as Norwegian from BCN.
- American tourism is exploding to some areas in Europe. Spain has had double digit growth for a few years (last year was about +22%). That probably has a lot to do with a number of reasons, such as EUR-USD exchange, lower oil prices, perceived risks in more areas of Europe / the world and finally Americans becoming more global and interest to travel abroad.
- Within Europe, it is obvious that due to recent issues some cities have been negatively impacted. Paris and Brussels have had large tourist drops (i.e. Japanese tourism is 50% down in Paris this year; that is massive). Southern Europe is the most benefited area, but also Scandinavia (so probably Norwegian, Icelandair, WOW and SAS benefit from this in their large expansion in North America).
- US and main core EU economies are probably "cooling down"
So looking at those routes, there is a clear trend. Routes for US passengers to leisure European destinations (Barcelona, Rome; even Amsterdam would be here in my opinion) are up. What is cancelled are destinations that depend more on business, local European traffic to the US (because they are not major leisure cities for Americans) such as Dusseldorf and Birmingham and/or have been affected by terrorism (Brussels).