Yes
Wix supports a mulitude of APIs to used for various fetch calls for your web pages.
If you already have to API's in mind you can venture off within you WIX code to integrate within your application's processes.
There shouldn't be any complications getting this done.
Please see the link below for more information

https://www.wix.com/code/home/api

Yes, it's possible please visit the below post for accessing third party services and information about api in wix.
https://support.wix.com/en/article/corvid-accessing-third-party-services-with-the-fetch-api

Wix doesn’t directly support APIs like Booking.com or other B2B travel platforms, so adding a flight search tool (like Expedia) to your website has some limits. Here are a few options:

1. **Custom Code with Wix Velo**: Wix has a tool called Velo where you can add code to your website. Some flight and hotel services let you use their API, so you could add a search feature this way. You might need a developer for this option.

2. **Use a Booking Widget**: Some travel services offer simple widgets or iframes (like a mini website) you can embed. If you get one from a travel provider, you can paste it into your Wix site to show a search or booking option.

3. **Whitelabel Solutions**: Some travel companies offer whitelabel products you can customize with your brand. They can sometimes be added to Wix as an iframe or link. You’ll want to check if Wix can support it before going ahead.

If you want a full booking system, think about a platform designed specifically for travel agencies too. It might work better than Wix for big features like flight booking.