i have Yosemite 10.10.5 on my mac air (early version 2014). Can I put El Capitan 10.11 or later on this mac air

The model year of a MacBook Air is available at Apple menu > About This Mac.

A late-2010 through mid-2011 MacBook Air can be upgraded to High Sierra 10.13.6 but no later version.

A mid-2012 MacBook Air can be upgraded to Catalina 10.15.7. See: https://support.apple.com/en-us/HT211683

A mid-2013 or later can be upgraded to the current version of Big Sur. See: https://support.apple.com/en-us/HT201475

If upGrading or desire to upGrade to Big Sur - some suggest upGrading to High Sierra first. Doing so will better prepare the computer. There will probably be Boot ROM updates when High Sierra is installed and converts the Internal Drive from the the old HFS Journaled format to the newer APFS format. That drive format will be needed if upGrading to Big Sur.

Tips How to Upgrade to Big Sur