Perhaps not 100 miles, but Autoroute reckons that the quickest route from Flughafen Hahn to Frankfurt is 75.8 miles..... Whereas from 'real' Frankfurt airport to Frankfurt it's 11.3 miles by road or only about 10 minutes on the S-bahn, not 1 hour and 45 minutes on the bus from Hahn!
Take your choice - low cost and a longer road journey (€12 per head one-way), or normal fare and a quick journey. Horses for courses.
But with buzz you used to have low cost AND a quick journey. M o'L admitted that they couldn't continue to operate STN-FRA due to the impossibility of obtaining the quick turn round time which the RyanAir operation needs in order to keep its prices low. Honest enough statement.