Book about children and hot air balloons, possibly steampunk

Question

I'm looking for a book that I read as a child. I don't remember too much about it, and I could be fuzzing up the details with other books I read in that time.

• The main characters were a boy, possibly his younger brother and I think a sister/female friend. They were either orphans or runaways who were on the run from BadGuy. I don't think BadGuy worked for any organization or anything, but there were several people after the main characters.
• The setting seemed Victorian/Edwardian London, and I think there might have been steampunk elements to it, but I can't think of any specific examples.
• Hot air balloons featured in the book. I think BadGuy used them, and towards the end the protagonists did too
• At one point, the scene I remember most, is that the kids are on a train. They either snuck aboard or they snuck something aboard. An uncle is with them and is either revealed to be working for BadGuy or else he's been with BadGuy all along and they're hiding from him. While on the train, there's a trunk with an object inside. The bad guys make off with the trunk, but the kids secretly got the object out before that happens. They get away, and this may be when the hot air balloon comes into play.

I read the book (possibly the first in a series) sometime between 2000 and 2006, I was between 8 and 13 years old and the book was targeted towards that age group. It was written in English, and I think it was a new book but it could just have been a recent print. Physically, I remember a book with a blue cover, I believe with a hot air balloon and the city below. I think it was about as thick as Harry Potter and the Sorcerer's Stone.

It's not The Thief Lord by Cornelia Funke, but it is in a similar vein.

Answer 1

This sounds one of Joan Aiken's novels, from the series following The Wolves of Willoughby Chase; perhaps the second book, Black Hearts in Battersea. The main characters are Simon, who's come to London to study painting, his friend Sophie, who was raised by otters (shh, don't ask questions), and Dido Twite, a street urchin. Together they get mixed up with the Duke of Battersea and end up foiling a Hanoverian plot against the life of King James, which involves escaping from an exploding castle (?) in a hot air balloon. At the end, it turns out that

Simon and Sophie are brother and sister, and inheritors of the Duke of Battersea.

Some editions do indeed have a balloon on the cover.

Several of the plot elements you mention are repeated throughout the series. In another book, Cold Shoulder Road, Is Twite and her cousin Arun are set against the Merry Gentry and their uncle Dominic de la Twite, a right bastard. Near the end of the book Arun is captured and put on a train to France. In Is, the title character's uncle appears to be on her side but is in truth an absolute monster. Is escapes on a train along with all the child slaves from her Uncle's foundry.

The stories are set in an alternate version of 19th century England, with James III on the throne instead of the Hanovers. It's a grungy version of England, with trains, a Channel Tunnel, industry, wolves and, of course, hot air balloons.

Answer 2

Sounds like The Court of the Air by Stephen Hunt.

When streetwise Molly Templar witnesses a brutal murder at the brothel she has recently been apprenticed to, her first instinct is to run back to the poorhouse where she grew up. But there she finds her fellow orphans butchered, and it slowly dawns on her that she was the real target of the attack. For Molly is special, and she is carrying a secret that marks her out for destruction by enemies of the state.

Oliver Brooks has led a sheltered existence in the backwater home of his merchant uncle. But when he is framed for his only relative's murder, he is forced to flee for his life, accompanied by an agent of the mysterious Court of the Air. Chased across the country, Oliver finds himself in the company of thieves, outlaws, and spies, and gradually learns more about the secret that has blighted his life.

Soon Molly and Oliver will find themselves battling a grave threat to civilization, an ancient power thought to have been quelled millennia ago. Their enemies are ruthless and myriad, but the two orphans are also aided by indomitable friends.