Did you know that Southwest and United Airlines both offer Senior Citizen Discounts for air travel? That gives me something to look forward to as the years fly by! LOL!
From http://traveltips.usatoday.com/airlines-offer-senior-discount-rates-63888.html
"Southwest
Southwest Airlines (southwest.com) offers senior fares to travelers who are 65 or older. Senior fare discounts are fully refundable and offered online, over the phone and through travel agents. Seniors taking advantage of the discounted fare must present proof of age, such as a driver's license, upon arrival at the airport or complete Southwest's age verification process by visiting the airport with proof of age or mailing a copy of the age document to the airline in advance of the flight, to complete online check-in.
United
United Airlines (united.com) offers senior fares, when available to those ages 65 and older. Travelers who select senior fares must bring proof of age to the airport to take advantage of a discounted rate. Seniors who are already part of the Silver Wings Plus program are able to purchase fixed-rate zone fares for themselves and a travel companion."
that sure is closer than the 65.
Not sure about United, but on SW these are not the typical discounted fares - but rather a less costly, fully refundable fare. Also, SW requires a senior to be 65. Since this is will be the big year for me 
I have checked SW fares often - the senior fares are much higher than the discounted web fare, or any other special fares. I just booked SW for January and chose the web fare because it was over $100 less each way than the senior.