Travolta's 707 does have a hushkit, but is the only one that has that hushkit. The certification was yanked after the methods used to certify it came into question. That is the reason there is only one 707 with a hushkit. You can't make accoustic panels by drilling holes in the hardwall panels that are there and expect them to behave like the honeycomb panels that present on commercial jets today. The only reason the FAA allows Travolta to fly his 707 in the USA is because he flys non rev. Non Stage 3 flights are allowed into the USA for repair.
