On reaching the airport, Tom found that he had left his bag in his home.
When reaching the airport Tom found that he had left his bag in his home.
Which sentence is correct?
What is the difference between them?
Edit: It is a question in a text book and I have no idea about the difference.
My guess is that the sentence with “on” equals “on reaching that point” which means immediately when he arrived that he found that he had left his bags.