Well Sunsetter and at least one other company make telescoping flag poles. I prefer metal to fiberglass myself
http://www.sunsetterflagpole.com/ <- Metal poles
http://www.wonderpole.com/ <- Fiberglass poles
Read the documentation on the poles and you will understand why I like metal better
NOTE put Telescoping Flag Poles into Mr. Google's famous web site and.... A lot pop up