Regarding the ban of firearms on commercial airplanes, the situation is entirely different. While possible sudden decompression certainly makes a firefight on a pressurized aircraft more dangerous (though not automatically catastrophic, as has been pointed out), that is not the real reason they've been banned (successfully) on airliners. As has been demonstrated, this ban did not guarantee safer airtravel, since boxcutters were responsible for over 3,000 deaths on 9/11. The airline gun ban has, aurguably been effective and reasonable, but ONLY because of the physical security measures that accompanied the law. You see, it is immoral (and unconstitutional) to deny a person the ability to defend themselves, unless adequate measures are take to insure that those who won't voluntarily comply with the law (i.e. criminals/psychopaths) are likewise disadvantaged.
In the case of airline travel, it has become very difficult in deed for someone to ilegally sneak a firearm on the plane, due to the multilayered physical security measures in place. It is, however, very expensive to so so, and would be impractical but for the limited number of commericial airports in the country. In the case of commercial businesses, limiting the lawful carry without cooresponding physical measures to prevent the unlawful carry is not just immoral, but in fact invites the evil doer to choose these spots for their crimes (who will stop them?). But with many hundreds of thousands of commerical businesses, the cost of doing so would be astronomical. Hence, there are no laws requiring businesses to ban guns. This is perfectly fine, since patrons can choose not to enter a business, if they don't like the policy.
Case in point: Here in Colorado, it was until very recently against the law to conceal carry on University of Colorado campuses. A suit was brought, where the plaintiffs argued that this policy created killing zones, since it deprived the law abiding a reasonable means to counter the criminal. The CO supreme court (in a rare show of common sense, in my view) agreed with the plaintifs. They ordered the CSU regents to discontinue the ban on any building, UNLESS, every entrance to every facility on campus normally unlocked to the public had a working metal detector installed and manned anytime said access points were open.
The bottom line is, asside from the mag restriction already pummelled to death here (and historically, tried with little to no effect), I still haven't heard any other ideas. Any time you ban anything, it represents a loss of liberty. Sometimes that is deemed acceptable by the majority in society. However, liberties give up have a tendency to never return (the ASW Ban being an acception, but only because it had a sunset clause included...otherwise it would never have passed). Before any item or behavior is banned by government, it MUST be reasonably established that doing so will be effective. Remember, what they ban today may be of no concern of yours, but what they ban tomorrow, using similar or even the exact same rationale, may be something very dear to your heart. If you won't stand up to another's rights, what expectations should you have that others will stand up for yours?