American Airlines quietly introduced two new travel policies last week — one of which is a negative development for passengers, and one of which is an overall positive.Want more airline-specific news? Sign up for TPG’s free new biweekly Aviation newsletter!Under the first policy, the airline will charge passengers a checked bag fee if their carry-on bag does not fit in the gate-side bag sizer and is gate-checked.Passengers who would normally be entitled to a free checked bag — including AAdvantage elites, passengers flying in a premium cabin, or certain co-brand credit cardholders — will still get the gate-checked bag for free.The second policy change is a bit more obscure, but good news for those travelers who can benefit from it.Previously, if a parent was traveling internationally with a lap-infant — a child under two, who could sit on the parent’s lap for about 10% of the cost of the parent’s ticket — was upgraded, then the basis for that infant fee would based be the new premium seat, potentially raising costs.Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.Now, American will not require them to pay the difference on the infant ticket — the cost stays the same, based on the originally purchased seat — even if it was in a lower cabin.Lap infants on domestic itineraries are still free.More: Long airline hold times continue as Americans race to book spring and summer travelBoth policy changes were first spotted by the View From The Wing blog, and confirmed by TPG.