Open Skies has a slightly different model. They have two classes of service on each of their jets. One is first class and one is supposedly interchangeable with L'Avion with identical seats and service.

They ran a three day sale, which I couldn't take advantage of, since I had already bought my seats, which offered RT first class for $2200 and bus class for $1400. In retrospect, for a 6 hour flight, the business class seats were fine for the price differential.

You don't seem to have to buy your tickets too early. There were plenty of seats. Open Skies and L'Avion were just combined in December, so you can go out on one and back on the other.

To Paris from Orly, it cost about $27 euros, including luggage though it can cost more if there is traffic as it is meter run and it depends where you are going. It took about 45 minutes. I found it a very easy airport to navigate, Passport control was easy and luggage and taxi were a snap to navigate. I had never been through Orly before. Taxis accept credit cards if you ask them first.

Luggage restrictions were very lenient. I had two HUGE and heavy suitcases filled with gifts going out for friends and I refilled them with wine going home. I had no problems. I also had two carry-ons. The XMAS markets have loads of liquid food stuffs you may want to bring home, so you can comfortably do that,

You also get 125% or 150% BA miles for either of these airlines-more for Open Skies.