Can I record hdtv programs on a vcr and then playback on a hd TV set ?

VCRs are old technology (comparatively speaking), and I haven't seen any that will record HD programs in HD. In most cases, you can find an composite video output and a pair of audio outputs on one of your devices that will connect to your VCR. It will then record the analog signal and you can play it back on your HD set -- but only in low definition.

If you're using an older VCR, and if you're taking the signal straight off the air, and if your only tuner is in the ATSC tuner (digital tuner) in an HDTV, you either have to convert the signal to NTSC (analog) or connect the baseband video to the VCR. Most likely, you won't have much luck.

There may be some newer VCRs (if they still make them) that have ATSC tuners in them.

--------- added later

I did find a JVC Video Cassette Recorder that is available with an ATSC tuner. It also will record in HD, SD, or analog:

Digital VHS HDTV Recorder - HM-DT100U - Features (http://support.jvc.com/consumer/product.jsp?modelId=MODL027315&pathId=50&page=2&archive=true)