What are the similarities between the first and last dream in "The Secret Life of Walter Mitty"?

I think the similarities seem to lie more in the kind of heroic
display of character that Walter Mitty is able to make in both daydreams rather than the actual
situation. However, we can perhaps find some similarity in the way that Walter Mitty always
chooses impossible situations for his heroic persona to face in his daydreams. In the first
daydream, Walter Mitty is the commander of a plane who has to go through a massive storm. His men
are terrified that the aircraft will be destroyed in the storm, but Walter Mitty insists they go
on through and we are shown the admiration with which he is regarded by his men because of his
bravery and leadership. The last daydream features Walter Mitty facing the firing squad and
scornfully rejecting a handkerchief to blindfold his eyes. Notice the way he is described at the
end:

Then, with that
faint, fleeting smile playing about his lips, he faced the firing squad; erect and motionless,
proud and disdainful, Walter Mitty the Undefeated, inscrutable to the
last.

Both daydreams represent escapes
from an overbearing wife, quite ironically in the last one, as it presents death as preferable to
being with her, but at the same time they show a tragic inability to confront Walter Mitty's own
problems by creating this do-or-die situations that, in his daydreams, he can
resolve.