irishguy28

I know DL's slate expands considerably in CDG at summer, but wasn't sure about LHR.

Delta, having previously been shut out of LHR completely (until fairly recently), has had to scrabble and struggle to get good slots there. I wasn't aware they were able to secure (comparatively many, relatively speaking) extra slots for seasonal services, given the demand, and the grandfathering rights of the incumbents!

orbitmic

Yes, it is quite impressive, and I'm not entirely sure what happens to those slots in the winter season. "Someone" must be having fewer flights in peak summer to make this possible. Admittedly, after arriving into LHR, they soon received the NW slots, and some AF slots that the French airline transferred from their Paris route to boost transatlantic traffic (remember the lovely LHR-LAX and short lived plan of an AF-operated LHR-JFK?) I suspect that they then bought some of AZ slots which were useable for long haul traffic, and very much suspect that they then received some from AA-BA as part of the conditions of the AA-BA anti-trust approval. When you start adding the new VS JV and think of the two airlines as proposing an offer, they are most definitely aiming to offer a true alternative to the AA-BA giant. As many have mentioned, it is hard to tackle such a dominant partner so it will be interesting to see if they manage, but at least, they are clearly aiming to offer the breadth and frequencies (notably on the uber competitive London-New York star route) to be credible even though DL are delaying their own-operated LHR-ORD.

On a separate note, I've always been interested by the fact that European airlines tend to have two seasons (winter and summer) with a certain amount of tweaking and reinforcement at different times of the year (reductions in mid-winter, reinforcements in mid-summer, etc) while US airlines seem to work on the basis of a 'genuine' six season pattern with great variations across al of them. As a result, airlines like DL have extremely low transatlantic frequencies from January to March and a lot of equipment changes and higher frequencies in June-August. I imagine that the relatively lax regulations in the US make this adaptability easier but I wonder if it gives them a comparative advantage over European competitors.

NickB

The winter/summer divide is based on the IATA scheduling seasons, which divide the year in two seasons. Those seasons are used for a number of not just commercial but also regulatory purposes, not least slot allocation.

The tweaking you describe does not work at "coordinated" (viz slot-constrained) airports in Europe: you could not operate a flight from January to March at LHR and leave the slots free for the rest of the winter season as you would lose your entitlements to the slots. You can play around by moving slots from one service to another but this represents relatively little room to play for a US airline. AFAIK, North American airline schedules at LHR (like most other airlines for that matter) are pretty stable throughout the whole season.

orbitmic

Thanks for the info on slots allocation by season, it answers a lot of other unanswered questions that I had! ^

The main difference between the 6 'cycles' (I'm using a different word to avoid confusion) is indeed mostly for domestic flights, although there are definitely many DL services that are suspended specifically from January to March (but operate in the earlier part of the winter season: early Nov-early Jan), notably some transatlantic frequencies to France (both CDG and NCE), and the cycles also correspond to some aircraft changes which might be a more subtle way to manage capacity, and slight timetable changes (e.g. the arrival time of LHR-SEA changes by a few minutes for each cycle).

For LHR, to give a specific example, the second daily to DTW (DL 19) only operates from 2/7 but not during the first part of the summer season. Or is it a more permanent change? If not, as you say, it may well be internal tweaking but not with another DL route as far as I can see so not sure if there is some form of slot 'renting' or sharing at different periods?

irishguy28

DL acquired slots from AF/KL in the past, and presumably can do so now with VS (AFKL may be less willing to facilitate slots for DL now that fall outside of their Joint Venture) so presumably this is where such slots come from...