After years of urging from consumer groups and authorization from congress, the Department of Transportation finally issued a legislative proposal requiring airlines to seat children age 13 or under adjacent to a family member or accompanying adult without paying a seat-selection fee. I can't believe how long it has taken DoT to reach this point, but here we are. You can expect final action soon.

You can also expect some airlines to contest a new rule. They will follow their long-standing pattern of response to consumer complaints. Normally, they ignore obvious consumer pain points indefinitely, even if they could easily fix the problem on their own.

Then, when the mass of complaints becomes overwhelming and the DoT issues a rule, they whine about "excessive regulation." The new rule will benefit just about everybody who flies: Travelers without children will have the added freedom from what often happens now. Flight attendants, dealing with separated families during boarding, typically try to arrange an ad-hoc accommodation by asking an unrelated traveler to switch seats so that a family can sit together.

All too often, that means asking a traveler to trade a paid-for aisle or window seat for a detested middle seat—a really inferior product no matter what airlines claim. The proposed rule applies to "an air carrier or foreign air carrier," without any additional detail. So far, four of the 10 airlines DoT considers as "large" have voluntarily made a commitment to fee-free .