Strasbourg to which airport to head home this fall?

Frankfurt has direct flights to Detroit operated by Lufthansa and Delta

Frankfurt is 2 hours by train from Strasbourg

I agree that Frankfurt would be my choice. Apart from the trains, Lufthansa also has a coach route between Strasbourg and Frankfurt airport so you can get the whole trip on a single ticket.

If you look at the Lufthansa bus from Strasbourg, it appears that it must be booked in conjunction with a Lufthansa or partner airline. Since the OP would be booking with Delta, the only airline with direct service to Detroit from Frankfurt, this seems problematic.
https://www.lufthansa.com/ao/en/lufthansa-express-bus#frankfurt

2.1. Carriage must be booked and paid for on lufthansa.com or at a travel agency before commencement of travel. It is not possible to pay the fare on the bus. The contract comes into effect with the electronic confirmation of the booking.

Lufthansa has daily direct flights from Frankfurt to Detroit.

You're right, but the multi city Lufthansa ticket Detroit to Switzerland and return from Frankfurt is significantly more expensive than Delta. Detroit is a Delta fortress hub.

That’s true…the multi city route is higher than I’d like. I’ve been trying other options, including flying Icelandair…and not getting any real bargains.

We have flexibility in when we go and the route…any advice about using tools to search for best days to travel in a more open ended way?

Thanks!

I use this site to put in flexible days. You still book directly with the airline.
https://matrix.itasoftware.com/search

CDG is fine as an origin/destination. No real issues. The tough part is transferring there.

Don't be afraid to cast your eyes around a little further and consider some more creative options. You might be surprised at what you find.

We will also be ending a trip to France this September in Alsace (specifically Colmar, just down the road from Strasbourg). I was looking for good options to fly home from somewhere within striking distance of Alsace (for us, home is Seattle, so we have far fewer good options for flights from Europe that can get us all the way home on the same day as our departure - those options are always limited for us, especially if we are not starting our day in a major European hub).

I eventually booked our flights home starting in Zurich, flying first to Istanbul then a nonstop to Seattle (all on a single, remarkably cheap ticket). It was crazy cheap for business class all the way from Zurich to Seattle on Turkish Airlines. (We used FF miles to book the flight but it was quite a bargain). Yes, of course, it requires starting in Zurich (a few hours by train from our starting point in Colmar), and looking at a map most people would consider it completely insane to start by flying east, all the way to Istanbul. But it's all in a very comfy Business class, and delivers us home to Seattle in comfort on the same day as our departure (though admittedly, we will need to reposition ourselves to depart early morning from Zurich). We'll enjoy the scenery on our bonus train ride to Switzerland and will get an evening to explore Zurich, too.

I'm not necessarily suggesting you consider the exact same routing (we caught a great deal on the flight, months ago, and I would not expect to replicate it) but what I'm saying is that you have many, many more options than just departing from FRA or CDG if you are willing to go looking for other routings.

The way I look at it, European train networks open up a lot of options for one's departure point if you're willing to get creative. In our case, looking a bit further opened up a really cool option that I know we will enjoy, even if it takes us a little out of our way geographically (that extra distance is a drop in the bucket). I looked at flight options from many other cities within a few hours train ride from Strasbourg - and that includes a lot of cities and hundreds of routing options. YMMV but there's a lot to choose from. Good luck!

Thank you, David, for sharing your insights! Lots of good info to ponder. I’m glad you got such a fantastic deal!

That’s one nice thing about having flexibility…the options are wide ranging! We were even looking into a stopover in Iceland. Now I’m thinking maybe a stopover in Portugal…if those still exist!

I’ve got a little time, but I’m eager to pin things down.

Thanks,
Laurie