The airlines are in the human shipping business. Larger humans cost more than smaller. Heavy objects consume more jet fuel. Weigh and measure each human like Fedex or UPS, stick a readable bar code on each passengerâ(TM)s neck, scan on entry. Route each human to appropriate storage area. Tranquilize if necessary or requested.

When a resource is scarce and desired, CHARGE for it by weight! Seems to me like travelers value overhead space more than checked space, charge accordingly! Charge even more for the space actually over your seat! The airlines will make more money and fewer travelers will bring huge heavy wheelies into the cabin! Boarding will be much faster!