I really appreciate your reply. So to continue with this line of thinking about 90 minutes being short even without luggage...the next question for me is can I check-in online (or UAL app) with the second PNR and walk from the KRK-MUC gate to the to MUC-IAH gate? Or do I need to check-in physically at the gate outside security since passports are involved? If I booked all with one PNR I would skip this? It looks like I may need to rebook a LH 6AM flight from KRK to MUC to safely make the 12:20P TATL flight. Again, thanks for this information as I have not been to Europe in a long time.