Books like Castle in the Air
Diana Wynne Jones
Castle in the Air is 298 pages, about 5 hours 28 minutes at 250 words a minute.
12 books to read next
How long each takes
Northern Lights 7.5 h 
The Little Prince 1.8 h 
Eragon 10.6 h 
The Sword of Summer 9.4 h 
The Iron King 2.3 h 
A Court of Frost and Starlight 4.8 h 
Peter Pan 1.8 h 
The Firework-maker's Daughter 2.1 h 
Over Sea, Under Stone 4.6 h 
The Rithmatist 8.2 h The Guardian of the Realm 5.8 h 
Wild Born 4.1 h Bar height shows length. Estimated at 250 words a minute.