Apex domains cannot have CNAME records.
Question and response
Question
dig hangar1flightcenter.com. NS
Answer
hangar1flightcenter.com. 5 NS ns-1871.awsdns-41.co.uk.
hangar1flightcenter.com. 5 NS ns-254.awsdns-31.com.
hangar1flightcenter.com. 5 NS ns-225.awsdns-28.com.
hangar1flightcenter.com. 5 NS ns-1435.awsdns-51.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0