Using 老头 / 老头子 when speaking to others I'm trying to get some clarification on whether or not it is impolite to use 老头 / 老头子  when speaking outside a group of friends when referring to a third party.

From my understanding 老头 is quite casual and I am interested to know if using this to describe someone's elder when also talking to another person who is also my elder, it may sound condescending?

Maybe I am completely off the mark because I understand that something 老王 is fine when referring to an elder and the use of "老" here is not a problem.

If this is somewhat impolite, is there a better word I can use similar to 老太太 to describe an older male?

Example sentence:

我今天看到一个老头在喂鸽子
The counterpart of 老太太 could be 老先生. It has a sense of showing respect. You can also say 老奶奶 (female) and 老爷爷 (male), which is more neutral.

Personally I feel 老头 is impolite, especially when combined with "一个" as in "一个老头". I'd rather use 老人 to say 我今天看到一个老人在喂鸽子, of course, this doesn't imply the gender of the old person.

老头子 is more commonly found in how an old woman calls her husband... Depending on the context it could have positive or negative connotation.