Will I make my connecting flight?

I am flying from Osaka (KIX) and landing at Narita at 2:35pm. I need to board a 3:20pm flight (45 minutes in between) to Detroit, Michigan, United States. Is there any chance that I make the flight to Detroit?

No, there is no chance.

You won't be able to make that as you still need to pass through Customs and Immigration before you board the plane! Were these flights booked separately, or on the same itinerary?

Depends. Are both flights on the same ticket? Will you have checked luggage?

The flights were booked by a travel agency with the same itinerary.

To have a good summary of your ticket, you can use checkmytrip.com: just input your six-character reservation code and your last name. If both flights are shown, then indeed it means that both flights are on the same ticket.

There may still be complications, however. Most importantly, what are the airlines for both flights? If they are not in the same alliance, it is possible that you will have to check-in for your Narita-Detroit flight at Narita, which could make a big delay.

It will probably be OK since both legs are on Delta, which runs KIX-NRT specifically to feed their ex-NRT flights.

Also note that Delta 172 KIX-NRT is considered an international flight, so you will pass thru immigration control at KIX. The transfer at NRT will be international to international and will not require additional time.

http://www.delta.com/content/www/en_US/shop/deals-and-offers/deals-fro...

Sounds like you will be on transit only. I was in a same situation once, was given 30 min, and was very worried then. But turned out no issue.

"transit vs transfer"
Transit means people on the same flight/plane/airline. For example when a plane lands to refuel.
Transfer means people switching flight/plane airline.

@jh The flight times on your link don't match those in OP. But it's very surprising that Delta is doing this, they could codeshare with ANA or JAL instead...

As previous posters have said, if both flights are on a Delta ticket (code sharing as well), then they need to ensure you don't miss the flight. They should meet you at Narita when you land and help you to get to the US bound gate in time.

They did this with us in Hong Kong when our flight was slightly delayed to Beijing on the same ticket.

When you check-in at Osaka, they will let you know what will happen. The bags should be checked all the way through to the US. Make sure you get there with ample time in case they need to juggle flights or something.

Delta is not part of the ANA or JAL alliances, they are SkyTeam, so I don't think they'll be code-shared with either one.

There are many cases where airlines in different alliances codeshare. Air France codeshares with JAL, for example.

Delta isn't one to codeshare with Japanese carriers.

https://en.wikipedia.org/wiki/Delta_Air_Lines#Codeshare_agreements

Can you read, or what? I know they don't, but I'm wondering why. There seems to be no advantage in flying their own plane.

Yes I can read, Mr. Know It All. That's why I responded to your, There are many cases where airlines in different alliances codeshare. Air France codeshares with JAL, for example. with my response. This is one case, of many, in which your comment is NOT correct. If you knew this to be true, why all the unnecessary ranting?

Flying their own plane makes sense to me though; it allows Delta to provide their passengers with almost direct service to KIX without the hassle of customs and immigration at the intermediate stop.

Not sure how it's going to work out in the long run though as Delta is intent on moving its NRT base to HND.