How can I remove Air Travel selection from my app services?

Where exactly did you select this ?

On appstor page ?

If app was not submitted yet, you should be able to change it on the same page.

On app entitlements ?

Then upload a new build without it

If I'm not mistaken, they prompt the service selection when I was submitted the build for review for the first time after creating the app in the App Store Connect. They only asked once, but I'm sure its not the category in the App Information section. I tried to upload new build, but the service selection never appear again.

I'm sure it -is- the Category. There is no other ASC meta data 'services'-centric flag.

See https://developer.apple.com/app-store/categories/

So that's when you declared the app.

On the appstore:

- select the app in "My Apps"

- select Information about the app on the left

- You should see category and sub category on the right.

When the app was submitted for the first time, apple has rejected the build with the following message:

"Per section 5.1.1 (ix) of the App Store Review Guidelines, apps that provide services or collect sensitive user information in highly-regulated fields, such as healthcare, should be submitted by a legal entity that provides these services, and not by an individual developer."

Which refers to,

"(ix) Apps that provide services in highly-regulated fields (such as banking and financial services, healthcare, and air travel) or that require sensitive user information should be submitted by a legal entity that provides the services, and not by an individual developer."

I remembered that I have selected the Air Travel previously, which is not the Category in the App Information section because I chose Lifestyle as the main category without choosing the secondary option.

As Apple states, they reserve the right to assign category differently from what the dev might choose. It sounds like it's out of your control now. Best to contact support directly for confirmation, link below.