Oops, it doesn't look like 'air and space museum day' is a national day..

Other days

lash

Lash Day
china

China Day
slime

Slime Day
raise awerness of zeus

Raise Awerness Of Zeus Day
bubble bath

Bubble Bath Day
law

Law Day
nae nae

Nae Nae Day
youth

Youth Day
bonang

Bonang Day
kale

Kale Day