Airlines often book legal-minimum layovers that look fine on paper but leave no margin in real life. A 45-minute domestic connection sounds doable until your inbound flight is 30 minutes late, your gate is at the far end of the terminal, and your connecting gate is in another concourse. Here's what to actually plan for.
The minimum legal connection time
Each airport has an official "minimum connection time" (MCT) that airlines use for bookings. These vary by airport and airline — typically:
- Most U.S. domestic airports: 30–45 minutes for connections within the same airline.
- Inter-airline domestic connections: 60 minutes (longer because bag transfers are slower across airlines).
- U.S. international arrival → domestic connection: 90 minutes (you need to clear customs).
- U.S. international arrival → international connection: 60–90 minutes (depends on whether you re-clear security).
- Major international hubs (London Heathrow, Paris CDG, Frankfurt): 60–90 minutes for normal connections, longer for terminal changes.
These are the legal minimums. They're not realistic for most travelers.
Why legal minimums are often too tight
The legal MCT assumes:
- Your inbound flight arrives on time.
- Your gate isn't in the far corner.
- The connecting gate isn't in another concourse.
- You don't need to re-check bags.
- Customs/immigration processes you in 15 minutes.
- Security re-clearing (if needed) is fast.
Any one of these going wrong adds 10–30 minutes to your transit time. Two going wrong and you miss your connection.
Realistic minimum times
For comfort, plan more than the legal minimum:
| Connection type | Legal min | Comfortable |
|---|---|---|
| Domestic, same terminal | 30 min | 60 min |
| Domestic, different terminal | 45 min | 75 min |
| International → domestic (with customs) | 90 min | 2.5 hours |
| International → international (no customs) | 60 min | 90 min |
| International, different airline | 2 hours | 3 hours |
The customs and immigration time
Arriving from international:
- Major U.S. hubs (JFK, LAX, IAD, MIA, ORD): 30–60 minutes typical, 90+ at peak.
- Smaller U.S. hubs (Boston, Detroit, Atlanta): 20–40 minutes.
- Mobile Passport Control or Global Entry: 10–15 minutes.
- Pre-clearance airports (Toronto, Dublin, Aruba, Bermuda): you clear customs before boarding the U.S.-bound flight, so arrival is treated as domestic.
Add 30 minutes for bag retrieval if you have checked baggage.
Terminal changes
Most U.S. airports have multiple terminals. Some are connected airside (you don't re-clear security); others require leaving secure and re-entering.
Major airports with airside connections between terminals:
- JFK: most terminals connected via train
- O'Hare: connected via tunnel and AirTrain
- Atlanta: connected via underground train
- Dallas-Fort Worth: connected via SkyLink
- Charlotte: walk-connected
Airports requiring re-clear (you exit security, taxi to another terminal, re-enter security):
- LAX: between some terminals, especially Tom Bradley to other terminals at peak times
- Newark: some terminal changes
- San Francisco: between terminals 1 and international
If you have to re-clear security, add 30+ minutes.
Same-airline vs different-airline
Same-airline connections: bag transfers happen automatically. Boarding passes for both flights printed at first check-in.
Different-airline connections: bag transfer is your responsibility unless airlines have a baggage agreement (some do; many don't). Often you re-check bags between flights.
Inter-airline connections need at least 30 extra minutes vs same-airline.
The "gate-to-gate" time
If you have a 60-minute connection:
- Inbound deplaning: 5–10 min
- Walk to gate: 5–25 min depending on distance
- Boarding for outbound: starts ~30 min before departure
So a "60-minute layover" leaves about 20–25 minutes of buffer. That sounds adequate, but if your inbound flight is 20 minutes late, you've used your buffer.
What if you miss the connection?
If the airline booked the flight as a single ticket and you missed because of inbound delay: they'll re-book you, no charge. You may sleep on a Hyatt courtesy cot if it's an overnight delay.
If you're on separate tickets (booked separately or with different airlines): you're on your own. The second airline can charge full change/cancel fees, often $200+.
This is why "tight connection" matters more on separate tickets than on through-bookings.
When tight is okay
Tight connections are fine if:
- It's a single ticket (airline rebooks you if delayed).
- You have only carry-ons (no bag to transfer).
- You know the airport (some airports are easy to navigate).
- You're flexible if you miss it (no critical meeting at destination).
When to avoid tight connections
- You have checked bags.
- You're booking separate tickets (especially across airlines).
- You're on the last flight of the day (no rebooking option until next morning).
- You have a critical reason for arriving on time (meeting, wedding, cruise, train).
- You're connecting through a small/unfamiliar airport.
Check your itinerary
Our layover time calculator takes your scheduled connection time and compares it to a realistic minimum based on whether you're connecting domestic or international, changing terminals, or rechecking bags. Use it before booking to know whether to choose the tight option or pay $50 for a longer one.