Plane reservations

Where are you flying from? That's a critical piece of information.

To me which airline is less important a question than itineraries, connecting cities and direct/non-direct.

I live in Jacksonville Florida but was going to fly out of Orlando since it is somewhat cheaper

I always fly PE unless I can upgrade to business which is rare these days and have flown delta, united and American out of Chicago. My least favorite was Delta because of the really uncomfortable PE clamshell seats -- I suspect less comfortable than coach. Food and service is a toss up between American and United. Food was excellent on our trip to Milan last week but not great on our last trip to Paris with them. Same with American -- hit or miss.

I fly Chicago to CDG with United with some regularity. No experience with Delta.

Why are you thinking Delta? I don’t lock into one airline unless I am using or collecting miles on a frequently flown route, the times are significantly better with one option over the other, I know the plane configuration or service level to be sub-par on a given route. (Example- I know the premium economy seating on an Asian carrier I used to use regularly was similar to Business class on a US carrier flying the same route. Easy to pick less expensive PE on the foreign carrier.). Of course, these are my decisions and you may well have your own reasons for preferring Delta.

You could post your question on FlyerTalk. Often there are very frequent travelers that can differentiate between different seating configurations and service levels for different airline options for a given route.

I don’t mean to be offensive, but I think you are over thinking this. I would go with the cheaper option when the price difference is as great as you state. My philosophy is to buy when I find an acceptable price and move on. Others have different strategies.

Well, if United is half the cost and all other things to consider (departure times, level of seats, layover times, etc) are about the same, certainly go with United.
If you haven’t already, check Google Flights for other options. Iceland Air flies from Orlando to Paris in May with a stop in Reykjavik that shows flights a bit cheaper. I’ve never flown with them, but they seem to have a good reputation.
I think you have time to keep monitoring flights, but I would want to get my flights no later than about 5 months before you need to leave.

Why January?
Check Google Flights for price history and set up price alerts. You can do a lot of research using this tool.
Good luck!

I figured January was a slow travel month and rates might be cheaper. I like Delta for the customer service. I won’t be able afford first class. Just one step above basic is what I’m looking at currently. I keep checking daily on Google flights. I’ll just go with what I can afford and hope for no delays. We are looking to fly in 3 days early for any hiccups

I like Delta because of it's safety and maintenance records. I've never flown United as I've always flown from a market where Delta was prominent. Is that actually apples to apples on price comparison? Wow to it being half of the Delta fare. Although to me, flying from and end of the line airport in the Inland Northwest, $1200-$1500 sounds pretty good for a fare!

I would look at prices around Black Friday. There are often some deals to be had around that time.

I've flown Delta's Comfort + class many times and have never had a clamshell seat. That must be on a particular model of plane. Perhaps because I have longer flights they use a different plane from the West Coast to Paris/Amsterdam? My seats have always been comfortable - a bit wider, more knee room.

On Delta, you may also get an offer to upgrade to Delta One. I've flown it a number of times and it is awesome. The lay flat seats are particularly good.

I'd try all different kinds of permutations. It looks like right now all the Delta flights from Orlando go via Atlanta anyway so you might as well fly out of JAX.

Also, you may be planning this anyway but try to arrive a few days ahead of time to give yourself some flex time for flight delays and hiccups!