you can add a line in the /etc/fstab for your flash drive:
/dev/sda1 /mnt/flash vfat noauto,user,rw,owner,umask=000 0 1
now, since you are using ubuntu, it will automatically detect the drive and mount in in /mnt/flash (make sure you create a folder named "flash" in /mnt)
and the "umask=000 " is necessary for vfat.
hope this helps you.