4Y 11 then UA 988 at Frankfurt
Cancún → Frankfurt am Main → Washington
Timetable, Frankfurt am Main time
11:404Y 11 from Cancún at the gate
11:30UA 988 to Washington leaves the gate
23 h 50 apart on the timetable, overnight
UA 988 leaves 23 h 50 after 4Y 11 arrives on the timetable: more than half a day, so not a connection we count.