Risky to book separate tickets for transatlantic flight?

A1) Do you feel lucky? Well do you?
A2) I will do it if I have a day or two layover but otherwise, no; not worth the risk for me.
A3) So rather than fight it, I would use it as an opportunity and spend a day or two in Copenhagen; some of my best travel experiences have come out of this sort of thing.
A4) If you go through with it, use nothing but carry-on as you will have to retrieve and recheck your bags and go back through security.
A5) With some luck (maybe) you can get your boarding pass for the second flight before you land in Copenhagen and not have to do security (use the connecting flight line); but again with carryon only.

I think that given all the recent flight cancellations, booking separate tickets is particularly risky at this time.

If you are on a single ticket and your first leg is delayed, then the airline is responsible for getting you to your final destination. They will put you on a later flight.

If you are on separate tickets and your first leg is delayed such that you miss your connection it is tough luck. You would have to purchase a new onward ticket.

Just to clarify (since my original post was longer and wordier than it could have been):

The outbound travel is DEN (origin) to CPH (final destination), and the connection is in KEF. So the two legs/segments are DEN-KEF and KEF-CPH.

Also, whether this travel is booked all together or as two separate tickets, it's all Icelandair.

Does the latter make any difference? e.g., would the airline be more accommodating about rebooking the second flight (due to the first flight being delayed) because both flights are Icelandair? Or likely not, since they are separate tickets?

Risky to book separate tickets for transatlantic flight?

Yes

Or, since they are separate tickets, are you out of luck and have to pay for a new flight?

This is correct.

If everything works perfectly you made save some money. If anything goes sideways, the cost goes up, and you could have an unplanned delay until there is an available seat.

It boils down to the question James E posed in the first response --- "Do you feel lucky? Well do you?"

If both flights are Icelandair, that connection through KEF is their
bread and butter sales pitch - one ticket straight through, zero need
for 2 tickets - you're on the cusp of really overthinking what is a
pretty simple daily process by the airline.

Well, the only reason I'm considering it is because doing it as separate tickets results in an overall $600 savings on air fare, versus booking one single multi-city reservation (or even a separate ticket that has DEN-KEF/KEF-CPH together on one reservation).

But yes, you're right about overthinking, except that I'm probably beyond the cusp ha ha. And maybe/probably the extra $600 is worth the peace of mind and mitigation of risk.

Thanks all!

Technically, you do NOT have a connection in KEF. You have two separate tickets. You may think of that as a "connection" and you clearly want to "connect" but to the airline, it's not a "connection". You may want to get the terminology clear in your mind before you start talking to the airline about it.

On one hand, you are taking a chance -- see Response #1 above from James E, his points are spot-on.

On the other hand, as you say, both tickets are on Icelandair, so you might expect a bit more customer-friendly policies and sympathy.

On the third hand (when you have three hands, things get complicated...) look at what you are doing: You do not want to pay them for the convenience and security of buying a single ticket all the way through, with a connection in KEF. That's what they are selling -- the security and the peace-of-mind of knowing that they will get you where you want to go, at a known price...but as you freely admit, that price is $600 more than what you are paying. You are in effect declining that convenience and security they are offering you, and (they might say) thumbing your nose at that, by being cute and saying "no, I'll just buy two separate tickets and save a buncha money!".

I don't know what will happen, and there's no way to really know without trying. Maybe the agents in KEF that day will be in a good mood, maybe they had a fight with their spouse, maybe they hate their job, maybe they will be kind and generous. Maybe they have a rule for this, and maybe they always follow the rules. Maybe they have a strong, very customer-friendly policy for this exact scenario and will do everything they can. Maybe the next 5 flights are all 100% full, or all are empty. Maybe they are operating on razor-thin margins, and look for every opportunity to monetize every opportunity. Maybe you will make the "connection" and you won't have to find out. Lots of maybes.

So you're back to the Clint Eastwood quote in reply #1, answer A1...

Not completely following what you are trying to accomplish. Why would you book to separate flights that are on going instead of a single ticket? Is it cheaper? The vast majority of our flights are open-jaw/multi-city. We have on a few occasions booked an on-going, discount airline ticket once we landed in Europe. We generally allow at least a five hour window to allow for late arrival, delayed immigration, etc. About three years ago we finally got burned. When our original flight from Denver to London was loaded, doors closed, and the flight was cancel for a mechanical problem. We thought we had covered ourselves by buying a full fare, changeable EasyJet tickets without reading the super fine print. We were three days late getting to London and lost that ticket. The point being is that you need to provide for a wide range of options if running on separate tickets. In your situation I don't see an advantage to a bunch of separate tickets. What advantage do you see?

I just plugged that data into Icelandair's website

1 ticket DEN-KEF - KEF CPH = $1,026

1 ticket DEN-KEF = $729

1 ticket KEF CPH = $304

I can't find the $600 savings?

Here is our specific itinerary, in case anyone's curious how I calculated the savings and why I was considering separate tix:

Outbound: Denver to Copenhagen
Return: Helsinki to Denver, with stopover in Reykjavik

• Doing this as an open-jaw multi-city fare on one reservation (2 adults, 1 child) with Icelandair totals $5,067.
• Doing this as 1 r.t. ticket DEN-KEF, 1 one-way ticket KEF-CPH, and 1 one-way ticket HEL-KEF (on a mix of airlines) totals $4,461.

Only that outbound portion is on the same day and thus higher risk. The return (HEL-KEF, KEF-DEN) is spread over different days.

In any case, I just booked it all on one single reservation, based on the consensus of good advice here. Thanks!

Traveling with a child internationally is difficult enough. Don’t buy those one way tickets.

Pick the ”stopover” option on the Icelandair site rather than multicity when you start the booking. If you do that, you are actually booking
DEN - CPH
HEL - DEN (clicking on stopover to add your nights in Iceland)

Can’t tell if that is what you did or if you booked the trip as 3 legs.

I think you made a good choice.

When you add the cost of all the Tums and Xanax you and the wife would need between now and the trip to the $44xx. the difference shrinks. Also eliminates the danger of an "I told you so" moment. :-)

Mike, I have done this more than once when flying to/from Europe. Yes, it is risky, but it has always worked out for me. So far I have been lucky. I've had hours, not days, between flights.

Whenever I've done this, I've looked at my contingency plans. I NEVER assume the other airline would do anything to help me at all other than following their policies about late/missed flights - meaning, I could be completely on my own. I might not get to my destination that same day. Or, I might wind up buying an expensive last-minute ticket to get to my destination that same day. At least, I understand what my options are before I set out on such a journey. If the consequence is acceptable (even if inconvenient), I do it.

My philosophy has been that if I do this over time, most of the time I'll make it. Could be I'll miss a connection finally next time and be out $$ to adjust. But over years, I will have saved $$$$$ by not booking expensive (or sometimes, very inconvenient) single plane tickets with one airline...and still come out way ahead.

FYI, it's possible some travel insurance trip delay policies may cover this kind of thing. I asked once and was told it did. You might look into that.

So...understand the consequences if you miss a connection, be prepared to live with them, and if you can't...don't do these flights on separate airlines.

OP has made his decision and purchased his tickets.

Beware that all airlines are not created equal. I have my favorites (that are reliable) and some non-favorites that may have some service issues. No names mentioned.

In the same way, I have preferable airports. For example, I remember one Friday afternoon in Chicago O'Hare where we sat on the runway 3+ hours to get out. Nix that place. I'm okay to fly out/in of Boston, but forget flying out of JFK. In the Southeast if you die and go to heaven, you've got to connect through Jackson-Hartsfield, and I'm okay flying thru there.

We're flying in 2 weeks to London, and we got a cheap flight from Huntsville to Charlotte and non-stop from there on American. Our last flight was BNA-ATL-AMS-BER--more connections than I care for especially since the wife was riding her travel scooter to the door.

When you start flying thru KEF, you may have a budget airline flying the second leg to CPH. From where we live, we'd prefer to fly BNA to LHR on a non-stop American Airways flight and connect to CPH. And 1 1/2 hour connections are okay where 4-5 hour connections are not.

Our last two international flights, post-covid, have had significant delays out of the US.
The Sept flight was canceled entirely, 24 hr delay, after we had boarded.
The April flight was delayed 4-5 hrs., as the pilot tested positive for covid.

Each time all of our connections were on the same ticket, so British Airways were responsible for getting us to our final destination.

Safe travels!