As usual, I think the term is respectful and appropriate. Or even older person. These do not necessarily mean incompetent or a lesser human being. Sorry but I am tired of having to say long, complicated verbiage rather than one descriptive word (unless it is widely determined to be negative).
I Googled "senior citizen" and got:
senior,
old person,
elderly person,
elder,
old fogey,
dotard,
Methuselah,
patriarch;
retiree,
golden ager;
superannuitant;
old stager,
old-timer,
oldie,
ancient,
wrinkly,
crock,
crumbly;
buffer,
josser;
oldster,
woopie;
geriatric;
senex;
retirer,
pensionary
pensionary
I do agree that there is ageism bias when looking for jobs. That's a whole different blog. My husband was fired after 25 years with a company and he had to (embarrassingly) accept a position that was ten levels down on the ladder. Because he was 50!! He did and after a year or two, was back in the game. Retired on his 75th birthday. Took the new company from $1M in sales to $65M in sales. See? Older people can be beneficial!!
Several of the terms above ARE derogatory although I have never encountered them in conversation or print. But I just don't agree that we need to come up with a new generalized group name. A fellow blogger suggested we be labeled as levels ..... like I would be Level 67. Then the higher we get, (like a video game), the better we sound!
I did read a great article (reprinted from The Washington Post ... who would not let me read it on their website). It was called "A New Term for Active Seniors: Call us Perennials".
Now THAT I could go with!