I'll soon be attending an event in Boulder that's scheduled to end at 5 PM sharp. I'm connecting to a once-daily international flight from SFO, so my choices are to either:

  1. Book an itinerary that departs from DEN at 6:55 PM, or
  2. Stay an extra day in Boulder, fly out the next day, and arrive back home a day later

Given likely rush hour traffic (I'll Uber/Lyft), TSA security lines etc, is option 1 feasible? Checking in online, no bags, but also no special TSA status (Clear etc).

Note: There's also a later DEN-SFO flight that would get me there in time, but due to the vagaries of airline pricing it costs $2000 more, which I can't really justify -- an extra hotel night is way cheaper.

  • Do you have TSA Pre, priority security, and/or Clear? How about checked baggage?
    – Doc
    Commented Aug 30, 2019 at 1:16
  • @Doc As noted above, no bags or magic TSA status. *G and mixed-fare itinerary, I'm in UA "premium economy" out of DEN. Commented Aug 30, 2019 at 1:25
  • No Premium Economy on DEN-SFO. I presume you mean Economy Plus? Either way, doesn't help in this case.
    – Doc
    Commented Aug 30, 2019 at 1:28
  • 1
    Is this a premium economy booking for the international flight? The third-party site may be doing some weirdness with the premium economy fare classes on the domestic leg to cause the $2,000 difference. If you haven't already, it could be worth trying United's site, other third-party booking sites, and ITA matrix to see if they all price it the same. Commented Aug 30, 2019 at 3:13
  • 1
    @Sam The AB bus from downtown Boulder station in my experience takes 15-30 minutes longer than driving to get to the airport because of the stops it has to make. Commented Aug 30, 2019 at 18:08

3 Answers 3


Personally I would consider this far to risky.

According to Google Maps, Boulder to Denver Airport at that time of day will "typically" take 40-70 minutes if you take E-470 (which is a toll road). Even if your Uber is pulling away at 5pm, that means you'll be arriving at DIA at 6pm.

Your flight will board at 6:05pm, so literally as you are walking into the door of the airport, your flight will start boarding. Boarding ends at 6:40pm, so you have a little over 30 minutes to find security (not as easy as it might seem!), make it through security (which at Denver can be slow - especially if you don't have PreCheck/Clear/Priority), get to the train, catch the train to (probably) the B gates, and then walk to your gate. Given you have Star Alliance Gold status you will be able to use the priority lane at security which will help a little, but even this can be variable.

Technically that IS possible, but you're going to need everything working in your favor to make it work - and especially given how long the security lines can be at Denver the odds of that happening are low.

United does have a "flat tire" rule which basically means that if you miss your flight they will try and put you on the next one at no charge as long as you arrive at the airport with 2 hours of the departure time of your booked flight - but that presumes there are seats available on the later flight which it's certainly possible there will not be so it's still a risk.

Personally I would not risk this - especially when connecting to an international flight. The Denver/Boulder area is beautiful (I was there yesterday!) and a great place to spend an extra day!

  • 9
    As someone who commutes daily between Boulder and Denver, I wholeheartedly concur with your analysis. There is no way I would ever attempt this. Commented Aug 30, 2019 at 2:26
  • 1
    Note there is a huge trick for Denver security: you don't need to go down into the cavern where everyone is lining up for security rather go to the skybridge towards the AA lounge, there's an empty security checkpoint on the bridge and an elevator down to the train at the end of the skybridge. Even armed with this I wouldn't attempt. But it's useful to know.
    – user4188
    Commented Aug 30, 2019 at 16:50
  • 1
    I've gotten stuck in that "empty" line for upwards to an hour; ymmv. Commented Aug 30, 2019 at 17:42

No. You can't do this. I've made this trip multiple times. It can't be done in two hours.


I've done this several times with no issues - just make sure your driver takes E-470, and don't be late. If you haven't missed a flight, you're probably wasting your time!

  • 2
    How does the link help in answering the question? It is a blog about not spending time in airports but it does not explain why not enough time to reach the airport magically makes him catch a flight locals doubt he can even see leave.
    – Willeke
    Commented Aug 30, 2019 at 17:31

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