The plane analogy doesn't work because dual engine planes are more reliable than single engine planes... unlike founding teams, engine can't decide that they want to go in different directions and engines are not insecure, ego driven, or prone to misunderstanding each other. Nor do engines have investors coming in sowing dissent between them.
If you look at the empirical evidence, you will see that most successful companies are started by an individual. Now, of course, a successful company needs more than one person to be involved-- they need employees. And early employees can be very well rewarded and significant contributors to shaping the idea.
But leadership by consensus does not work, as anyone who has belonged to a high school club or organization knows. In a business environment, it is death- the founders never reach consensus and generally they constantly pull against each other, undermining each other and ultimately undermining the company.
Leadership by consensus is quite literally the absence of leadership.
When there is a leader, and that leader is capable, the company succeeds.
If you have a pair of people who work well together, then as you concede generally one of them will be the clear leader. Dividing the work and having each lead sections of the company is fine- if you know the person who you can do that with. But such people are generally quite rare.
Unfortunately, the advice that you must find a founder in order to start a company is bad advice-- in most cases this will lead to the company failing. There are, of course, examples of pairs of people who co-founded companies together and they are well known because they are the exception. But the vast majority of successful american enterprises are started by an individual with an idea and the dedication to pursue that idea.
Forming a company takes vision. It takes dedication and it takes certainty that there is something there- and opportunity to add value that has not already been seen and seized by other entities.
This is why leaders who start companies are far more likely to success than friends who decide to "do a startup" and "manage by consensus."
If you don't have a cofounder already- you shouldn't be looking for one. Hire some employees.
But you're far from screwed-- simply looking at the history of startups in America and you'll see that single men with vision are most often the ones who succeed.