I'm unsure about the inflation. There were complaints from 1968 onwards about interest rates going nuts. My memory is the 1973 Arab oil embargo & oil price shock were the first serious inflationary items. Best to go dig up numbers.
The aircraft industry underwent some contractions about this time.
Stagflation is caused by a "negative supply shock" which moves the supply curve inward, as explained by this ol' country boy (actually, a high school AP teacher!)
Don't know why it was viewed as such a mystery for so long (journalists aren't economists perhaps?)