Div position in the middle of another vertical element - html

Question

I am trying to align flight duration time just in the middle of each flight path (blue line). But it doesn't work, duration (1:30) is not exactly in the middle of the line and text is not centred. How can I fix that?
CodePen code example
HTML:
<span class="col-md-12 roundtrip">
<div class="col-md-6 trip">Outbound
<div class="flight">Los Angeles</div>
<div class="flight-path">
<div class="flight-duration">1-30h</div>
</div>
<div class="flight">Chicago</div>
<div class="connection">5hr wait</div>
<div class="flight">Chicago</div>
<div class="flight-path">
<div class="flight-duration">1-30h</div>
</div>
<div class="flight">New York</div>
<div class="connection">2hr wait</div>
<div class="flight">New York</div>
<div class="flight-path">
<div class="flight-duration">1-30h</div>
</div>
<div class="flight">Amsterdam</div>
</div>
<div class="col-md-6 trip">Inbound
<div class="flight">Amsterdam</div>
<div class="flight-path">
<div class="flight-duration">1-30h</div>
</div>
<div class="flight">Los Angeles</div>
<div class="flight">Los Angeles</div>
<div class="flight-path">
<div class="flight-duration">1-30h</div>
</div>
<div class="flight">Amsterdam</div>
</div>
</span>
LESS:
.roundtrip {
display: inline-flex;
flex-direction: row;
align-items: stretch;
}
.trip {
width: 100px;
text-align: center;
border: 1px solid black;
margin: 0px 3px;
display: flex;
flex-direction: column;
margin-right: 50%;
}
.flight {
white-space: nowrap;
}
.flight-path {
width: 6px;
min-height: 85px;
flex-grow: 1;
align-self: center;
background-color: #6090FF;
position: relative;
}
.connection {
height: 40px;
color: red;
border: 1px solid red;
display: flex;
flex-direction: column;
justify-content: center;
}
.flight-duration {
position: absolute;
top: 50%;
transform: translateY(-50%);
white-space: nowrap;
background: rgba(255, 255, 255, .75);
width: 81px;
left: -38px;
text-align: center;
}

Answer 1

It seems like every time I want to align something vertically I go back to this link:
https://css-tricks.com/centering-css-complete-guide/
I like the way the use cases are organized.

Answer 2

You could try a table layout. Does this help?
.line {
width: 5px;
height: 200px;
display: table;
table-layout: fixed;
text-align: center;
}
.time {
display: table-cell;
vertical-align: middle;
background: #777;
height: 10px;
text-align: center;
}
span {
background: #ccc;
padding: 10px 0px;
}
<div class="line">
<div class="time">
<span>12:34pm</span>
</div>
</div>