I did a Goggle search 4th Liberty Loan Flag image search and came across the following which might help explain the symbology.

George Martin

"I recently acquired this flag. It reminds me of a Sons in Service flag with the red border and blue stars, but I have not seen a service flag with blue bars. Do you know what this flag actually is? It is 49 1/2" x 32 1/2" in size.
Pete Bochek, 12 May 2003

I was searching on eBay and stumbled across this Liberty Loan poster. What I'm guessing is that the number of stripes corresponds to the number of Liberty Loans a town has given to the Great War (World War I) I'm not so sure about the stars on the FOTW site. Kind of has me stumped. But I believe I have found the meaning behind the stripes. 
Jonathan Backstrom, 31 March 2004

The flag (note the picture is upside down) is one of two variants I have seen of the special award flag for the Third Liberty Loan of 1918. One with the two stars and one without - the two stars indicate municipality raised three times its allotted quota. The flag of the Fourth Liberty Loan, which is similar but has 4 vertical stripes and no stars. The Liberty Loans were national efforts to raise extra money for the War effort; the loans were interest-free (at least I think so; none of the literature mentions any) funds given by US Citizens and repaid by the US Government after the War. In many cases, the loaners forgave the loan after the War.

I am unaware if the First or Second Liberty Loan Drives had any flag associated with them, but by the time of the Third Liberty Loan, organizations, corporations or municipalities could sign up many individual donors to make the target amount and get a 3'x5' flag for their efforts.

I have always thought that maybe this design is a combination of the NSF and the proposed flag of the Four Freedoms that was briefly considered as a flag for the UN before the end of the War. That flag was white with 4 vertical red bars that did not touch the edges of the flag.
Dave Martucci, 5 April 2004"