If you disagree with your instructor's explanations, why is she or he your instructor?
This is not quite so cut and dry as you might think. There are those of us that are not rooted to any one particular community and relocate after several years while Aikido (or any martial training) remains a foundation of our lives. We are not particularly tied to any one instructor and at times are constrained by the availability of dojos wherever we happen to find ourselves living. Personally, my main instructor will always be the one I spent the most time with in Asia. However, several other instructors and friends whom I have met during my many travels exert a good deal of influence on my aikido. There have been times where I have found myself practicing in a dojo where the instructor has a decent foundation but pales in comparison to others. Often there are stark contrasts which sometimes make me cringe and there have been times where the presiding instructor seems to miss what I understand to be the basic underlying principle of the technique or motion. Sometimes you find small dojos in rural or out of the way areas where the instructor has been training a long time but has not had the same opportunities or exposure to really good aikido, and their rank may not equate well with their abilities.
If no other nearby dojos are available or in some case may actually be worse, what are the options? Is it fair to a community of people to try and start a new dojo, if you know you are only resident in the area for a finite amount of time? Should you attempt to influence the instructor or try to change their approach to the technique? What do you say if the person has been practicing 10 or more years longer than you? Sorry, but I think you have missed the point the past decade? What if you're only a Nidan or Sandan and the instructor you dealing with is a Yondan or Godan? How can you express the disagreement without coming across as arrogant or condescending?
Some of us come from a very rich aikido background and have in a short amount of time experienced a very broad and expansive introduction to not only aikido but budo in general. So what do you tell an instructor whose background and experience is limited?
These are hard questions to answer. Sometimes all we're looking for is a place to practice, and while the instruction may not be teaching me anything new, the availability of the mat space and partners to practice with is valuable. There are times where I felt sorry for the local deshi. The instructor lacked the ability to truly connect with uke and relied solely on uke for any type of connection. Most of the techniques were at times ridiculous, and even seemed spiteful in execution. Ukes had to receive coaching on when to actually fall. This was seen as a failure of the uke and not the actual technique. So, what's a person to do?