This is an increasing trend with a view to monetarising popular sites. By locking you into an app and then "improving" it the idea is to move you into a subscription model, which is where the real money can be made with popular sites.
Generally there is a button that allows you to continue to load and run the site in your browser. Failing that, you really are only left with the option to download the app. If you do decide to do this, go to the official app store for your device and download the applicatioon from there. Never follow the link from a random web page, you may be directed to a fake app store page that looks genuine but will attempt to load malware onto your device disguised as your new app.
Pilotpointer.com just loaded as a standard web page on my iPad, no sign of a redirect to a specific app. Try clearing cookies, etc., restarting your browser and accessing the site.