ICELANDAIR MODIFY BOOKING NO FURTHER A MYSTERY

What's "jam" necessarily mean in "The home reeled and he jammed his head down" (along with the sentence alone)? we're considering booking two distinctive flights, so would wish to collect our luggage, Examine it again in and so forth. we might be travelling to KEF from London on EasyJet, then out of KEF to Calgary on WestJet. The stopover time is