Castle in the Air - Diana Wynne Jones

Young merchant Abdullah leads a humble life. Or he did until a stranger sold him a threadbare--and disagreeable--magic carpet. Now Abdullah is caught in the middle of his grand daydreams. Waking one night in a luxurious garden, he meets and falls instantly in love with the beautiful and clever Flower-in-the-Night. But a wicked djinn sweeps the princess away right before Abdullah's eyes, leaving the young man no choice but to follow. This is no ordinary quest, however, for Flower-in-the-Night isn't all the djinn has stolen. Abdullah will have the so-called help of the cantankerous carpet, a cranky genie in a bottle, a dishonest soldier, and a very opinionated black cat. Will this motley crew be able to find the djinn's mysterious dwelling and rescue a castle full of princesses?