Originally Posted by
UAPremExecflyer
Traveling IAD-JFK-SIN on one ticket/PNR, your checked bag(s) go through to the final destination. No need to collect and re-check at JFK. Likely just change terminal.
If traveling on separate PNRs, then it's a different story. Depending on the airline combination(s) and if the same alliance (Star, oneworld etc) or not, then you may well have to claim at JFK and re-check.
Can through check even if travelling on different PNRs, and many times even if travelling with airlines on different Alliances.
At JFK, your mom will have to pick up the bags, clear customs, and then drop the bags off for the next airline.