It was a Friday.
It was a Saturday.
September 11th can be on any day of the week
That was a Friday.
Sunday
Monday
Saturday
The 11th of September 1958 was a Thursday.
September 11th, 2003 fell on a Thursday.
April 11th, 1970 fell on a Saturday.
It was a Sunday.It was a Sunday.It was a Sunday.It was a Sunday.It was a Sunday.It was a Sunday.It was a Sunday.It was a Sunday.It was a Sunday.It was a Sunday.It was a Sunday.
That date can be interpreted in two ways. 4 November 1970 was a Wednesday. April 11th 1970 was a Saturday.
It took off on Saturday the 11th of April, 1970.