If I purchase the ticket I will have 1 hour and twenty minutes to make a connection from my arriving domestic flight on Delta to connect with a international flight on Czech airline.
Will I have time assuming my incoming flight arrives on time?

If everything goes just right you may.Why take the chance.Get an earlier flight.

Will your lugage be checked through to Prague (?) from your original destination? If so, and if your Delta flight is on time you should be OK - since they're in the same terminal. If they won;t check your luggage through there is no way you can make this.

I would call Delta and check on this ASAP.

Other factors to consider: when is this flight? Bad weather--snow or even rain, fog(JFK is right near the water) winds, could easily delay a domestic flight by an hour. "Assuming my incoming flight arrives on time" is not very realistic" I'm afraid
Also, JFK does not have a simple internal train like other airports, so you need to get from one terminal to another--or are they in the same terminal??
One vote for "no, not enough time"

JFK does have the free AirTrain that goes from one terminal to the other. But that's beside the point as CSA Czech uses Delta's Terminal 3.

CSA Czech is a Skyteam member, and definitely has interline baggage agreement with Delta, therefore you can absolutely check your bags through to Prague from your original airport.

The US has no immigration checkpoint for people leaving the country, so connecting to Prague is just like connecting to any other airport on Delta. No difference. Therefore 1hr20min is definitely enough, acceptable and legal. If someone thinks that's not enough, then what is? 3 hours, 5 hours or 2 days?

Yea as long as your first leg has no problems your vacation to Europe won't get ruined.

rkkwan, I agree that everyone has their own tolerance point as to what is enough time. I still think that 1:20 is cutting it close, (as long as John was asking...) In the past few years, I'd say half of my domestic flights had some sort of delay, and one hour is not that unusual. Even in the same terminal, without having to check in luggage, you still have to get off the plane, go to the next gate, etc.

John, if you can switch to allow yourself an extra hour or so, you'll be less "pressed" for time. If not, things will probably go well--Good luck!

My concern at JFK is not whether I can make the next flight but whether my luggage can make it. We checked out luggage through to Morocco and easily made the flight. But our luggage did not, and we had to wait for two days to get it. An hour and a half may not be enough time for your luggage to be transferred.

Unlike many airports in the US, JFK is not dominated by a single carrier, and most of the terminals there are distinct in style, history, architecture. Each is usually run by a single airline and is seperated physically from other terminals.

Therefore, it's crucial to understand what terminal(s) your connecting airline(s) will be using. Apparently, say if you're connecting from BA in Terminal 7 to a Delta flight at Terminal 2/3, then your baggage will need a much longer time to get there as those terminals are like zip codes apart.

Also, while many of the terminals have been rebuilt recently like Terminal 1 or 4, Delta uses the Pan Am WorldPort built in 1972. So, a passenger's experience at JFK will be highly dependent on the airline being used.

And JFK's air traffic situation isn't too bad. Delays shouldn't be as bad as LaGuardia. And weather can affect any airport anytime, and again JFK isn't too bad with that either, compared to say ORD in the middle of winter.

As others say, it depends on your comfort level. I wouldn't do it unless you investigate and can live with the possible downsides of missing the connection. How much money and time will you lose? When's the next flight?

You should read this trip report on the Europe board. This poster had to pay more than $1,000 extra/person (x6 !!!)because her flight(s) from the west coast landed late at JFK due to weather. She "missed" her Air France flight to Italy even though the flight hadn't left.

http://www.fodors.com/forums/threads...2&tid=34527910

Yes, do think about what can happen if your first flight arrives late, and you miss the connection. JFK is one of the main focus point for DL's European operation; and CSA Czech, DL, Air France are all partners in SkyTeam. So, if you miss your 5:45pm non-stop to Prague, I don't think it'll be too hard for DL to fly you to Paris (either on DL or AF), and connect you to Prague on AF or CSA. Or DL to one of the other major European cities and then CSA to Prague. So, I think even if you miss your connection, you will still be able to get to PRG on the same day, later of course.

But of course, if you have an important meeting at Prague you have to go at lunch time in Prague, e.g., then you may want to re-consider your plan. And if that were really the case, then it'd be pretty foolish to plan to arrive that morning anyways.

If you are booking this ticket all as one reservation, I think rkkwan's point is correct, it's mostly about time. But if you're booking this combo ticket as two separate tickets (which is what I understand this poster did) buying one from Delta and the other from Czech air, in order to get on a different flight, they were forced to pay the price of the ticket on that day (same day ticket price) despite getting "credit" from their original ticket. So while they were able to leave only an hour or so later, it was $1,100 more/person.

Since Delta & Czech are skyteam affiliates, I'd call Delta and check on what would happen if your first flight is late. They are probably committed to finding you an all-new route. In other words, if the first flight is delayed, they won't put you on it...they'll make all new arrangements for you.