Sorry to say sir, but you're having a completely useless questionnaire for your research. As of real; there is no comparison between all three currently operating airlines in Pakistan. To elaborate it, i must say, that you can have a Nissan Sunny, a Toyota Corolla and a Honda Civic in one pool and compare them due to the reason that all three have nearly the same size of engine, they all have a boot, they're all are four seater sedan, and mainly offer the same features BUT you cannot compare a Pak made Suzuki Mehran, a Jap Vitz and a Brit made Land Rover; it will rubbish.
Coming to the point, which is nearly clear, that all three of the airlines in Pakistan have a different size of their aircrafts, different models, they all working at a different investment scale, difference in the size of manpower, and surprisingly they all serve a different target market which is mainly due to the difference between fares.
Shaheen is serving a target market who value money more than comfort and safety. They are mainly small businessman who travels by an airline more than a couple of times in a week or a month. Therefore, they consider the amount which they save by not traveling in the other two airlines.
Airblue is mainly serving the corporate sector of Pakistan where the companies are a bit conscious about the brand name in which their employees travel. And it also serves those who are opposite to shaheen's target market i.e. they prefer comfort and better service by giving away more on the fares.
Whereas PIA serves the elite department, mainly the government/armed/bureaucrats/foreign nationals and multi millionaire businesspersons etc, who never compromises over safety and comfortability by paying the sky high fares. They are very much curious for what their tag says on their baggage.
Therefore, all the three airlines are serving different type of classes, and a totally different target market.
Furthermore, in order to achieve the accurate/unchallengeable conclusion of your research you should better book one ticket of same destination from each of the three airlines and analyze by yourself. This way you will have the chance to observe those users of Shaheen airline (particularly) who don't even know what is internet so they could come over here and answer to your questionnaire.
Moreover, if you want to make your research more productive and beneficial for the Pakistani people than you should do a comparison between PIA, which is top ranked in Pakistan, with some foreign airline of international standard. This way you will be able to point out the flaws of PIA in becoming a world class airline.
Anyways, sorry to take lots of time. Best of luck. :)