JFK is IMHO one of LH's nicest and most convenient outstations for departures (for arrivals, less so ).

I have checked in at the LH desk for LH401 as early as about noon, but unless you have a good book or an electronic device with which to play, the F lounge will get boring quickly if you arrive that early. From the curb at Terminal 1, it is a good 20 meters to the LH F check-in desk, and then another 50m or so to the security line, which (at least a couple of years ago when I went through it regularly and was similar a few months ago) is a 10-20 minute exercise. From security, you look left (yes, left, oliver2002 ), and the entrance to the LH lounges (BUS/SEN/F, on three levels) is another 20m or so.

It is rare to require more than 30-35 minutes, and that is if security is crowded. With some luck, terminal door to lounge can be a little as 10 minutes, but if it were me, I would plan for 30 minutes, plus whatever comfort you have that the TSA will be working efficiently that day.

Boarding gates are also generally close to the lounge, so if you check in by 14:00 or so, you should have time to enjoy the lounge (including meal), and even do a little duty-free shopping right outside the lounge door, if that is your custom.

In short, I pretty much agree with the comments of the others.