Salaah

Salaah on an aeroplane

Q: How does a person carry out their salaah on a plane? Does it have to be re-read once a person lands? Is it true that a persons wudhu will not break if they sleep while sitting if their feet is on the ground? ( eg in flight)

Waiting for one's companions to perform Salaah in jamaat when travelling

Q: I would like to know the usool/adaab when travelling in a group and stop for salaah at a musjid where the salaah is almost finished. All the brothers in the group have wudhu but one brother doesn't have wudhu. Should all the brothers with wudhu join the jamaat leaving the one brother to miss salaah with jamaat, or should all wait for the brother making wudhu and perform another jamaat, or should most join the main jamaat and a few wait for the brother making wudhu and make another jamaat?