Apex domains cannot have CNAME records.
Question and response
Question
dig h6aircraft.com. NS
Answer
h6aircraft.com. 5 NS ns-1773.awsdns-29.co.uk.
h6aircraft.com. 5 NS ns-974.awsdns-57.net.
h6aircraft.com. 5 NS ns-173.awsdns-21.com.
h6aircraft.com. 5 NS ns-1412.awsdns-48.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0