Edit in JSFiddle

<div class="flex-container row align-items-start bg">
	  <div class="flex-item big">1</div>
	  <div class="flex-item">2</div>
	  <div class="flex-item small">3</div>
	  <div class="flex-item small">start</div>
</div>
<br>
<div class="flex-container row align-items-end bg">
  <div class="flex-item big">1</div>
  <div class="flex-item">2</div>
  <div class="flex-item small">3</div>
  <div class="flex-item small">end</div>
</div>
<br>
<div class="flex-container row align-items-center bg">
  <div class="flex-item big">1</div>
  <div class="flex-item">2</div>
  <div class="flex-item small">3</div>
  <div class="flex-item small">center</div>
</div>

<br>
<div class="flex-container row align-items-stretch bg">
  <div class="flex-item big">1</div>
  <div class="flex-item">2</div>
  <div class="flex-item small">3</div>
  <div class="flex-item small">stretch</div>
</div>

<br>
<div class="flex-container row align-items-baseline bg">
  <div class="flex-item big">1</div>
  <div class="flex-item">2</div>
  <div class="flex-item small">3</div>
  <div class="line"></div>
  <div class="flex-item small">baseline</div>
</div>

.flex-container {
  padding: 0;
  margin: 0;
  -ms-box-orient: horizontal;
  display: -webkit-box;
  display: -moz-box;
  display: -ms-flexbox;
  display: -moz-flex;
  display: -webkit-flex;
}
.align-items-start {
	align-items: flex-start; 
}

.align-items-end {
	align-items: flex-end; 
}

.align-items-center {
	align-items: center; 
}

.align-items-stretch {
	align-items: stretch; 
}

.align-items-baseline {
	align-items: baseline
}

.row           { 
  -webkit-flex-direction: row; 
  flex-direction: row;
  flex-wrap: wrap;
}

.flex-item {
  background: deepskyblue;
  padding: 5px;
  width: 50px;
  margin: 5px;
  line-height: 50px;
  color: white;
  font-weight: bold;
  font-size: 2em;
  text-align: center;
}

.big {
  width: 150px;
  font-size: 5em;
}

.small {
  font-size: 1em;
}

.line {
  height: 1px;
  width: 100%;
  border-bottom: 2px solid deepPink;
  position: absolute;
  top: 540px;
  left: 0;
}
.bg {
	background: #9E9E9E;
	height: 100px;
}