Would you suggest plane? What airlines service that airport?

or

Train and stopping in Heidelberg ?

Hi M,

There are many trains per day on that route. It's 1:35 hr.

You could buy a ticket for S/H and another for H/F and spend the day in H.

See www.bahn.de for schedules and tickets.

PS,

Check www.whichbudget.com for discount flights, but I think the train will be faster.

In the time it would take to get to the Stuttgart airport, check in the requisite time in advance, and wait for the flight to take off. . . you would already be in Frankfurt.

Ira, what's with the bulb at the end?

Hi R,

It's the icon that comes up when I sign (( I )).

Definitely take the train. The ICE (the fast train) gets from Stuttgart, making one stop at Manheim, in approx one hour (recommend spending 3 euros on a seat reservation). If you are flying Lufthansa by chance, you can check your bags at the train station and they will go directly through and loaded on the plane in Frankfurt. If you want to take a non-ICE train, stopping off and seeing Heidelberg is also a good idea. You would have to take a taxi or local bus to get up to the castle.

Ira. Original answer.