Hi everyone. My father is booked on an itinerary transiting through FRA and I wanted to do my due diligence to see if there are any issues to flag. I've read through this thread and it seems like his itinerary is decent.

Here are the details: two separate tickets with no checked bags: first is JFK-FRA on Singapore in economy, scheduled to arrive just before 10:00AM. Second is FRA-HAN in business, scheduled to depart just before 2:00PM. So the layover is four hours. I checked the (excellent!) airport map and seems like it's a not too far transfer from T1 to T2. Both flights seem to have solid on-time rates.

I assume a four hour layover is more than fine (as long as the inbound flight doesn't have severe delays) but are there any other red flags, security delays, etc. that I should be aware of?

Thanks!