One day Sarah and Malcolm wanted to go on holiday. They overslept because the alarm clock didnt go off. They managed to arrive AT the airport on time. The flight WAS (! opisując konkretne zdarzenie z przeszłości nie używasz present perfect, ani p.p. cont.) delayed. An airport stuff member informed them that there were two seats available on the earlier flight. Sarah and Malcolm sat near the Adams family, who were screamING and making terrible noise. When they landed, the Adams family went to a different hotel than Sarah and Malcolm. Sarah and Malcolm went to the hotel they had reserved before. (jakieś wydarzenie z przeszłości nastąpiło wcześniej niż inne, też przeszłe - czas zaprzeszły past perfect)
They got on a bus but it got a puncture so they had to get off it and take a taxi (dużo tych gotów, ale tak mi wyszło na szybko. może ktoś ma inny pomysł). Albo jeszcze tak: They had reserved a hotel before. While they were going to the hotel, the bus they were on got a puncture. They had to get off and take a taxi (ta druga opcja chyba lepsza).
They arrived at the hotel, and it proved to be an awful place. They asked their travel agent to show them another accomodation option. (The agent told them that) there was a room available in some other hotel. Sarah and Malcolm went there but it turned out that the Adams family had chosen it too... It was a terrible holiday ...
nie wszystkie poprawki wytykam wielkimi literami czy w nawiasie - przeczytaj i porównaj ze swoją wersję. Może ktoś jeszcze coś zaproponuje, np z tym stuff member - worker mi tu nie pasuje. pzdr