HTML – flex属性混乱按钮高度？

目前按钮正在占据容器的高度.文本下面有很多空间,我想删除i,当我向按钮添加填充时,它的大小会变得不均匀.我试图通过线高调整大小,但我试图找到实际的解决方案和原因,为什么我有这个问题.

我在这里缺少任何与flex相关的东西,还是其他东西？
任何帮助将受到高度赞赏.
谢谢.

.vessel-card {
  display: flex;
  flex-direction: column;
}
.vessel-card h3 {
  margin: 0;
  padding: 20px 0;
}
.departure-card {
  display: flex;
  padding: 20px 0;
  border-top: 2px solid #888;
}
.departure-card p {
  margin-right: 10px;
}
.departure-card:last-child {
  border-bottom: 2px solid #888;
}
.departure-card .btn-explore {
  border: 1px solid #000;
  display: inline-block;
  text-transform: uppercase;
  color: #000;
  border-radius: 0;
}

<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet" />
<div class="container">
  <div class="row">
    <div class="col-md-4 vessel-card">
      <a href="cienfuegos-from-havana.html" class="special-departure">
        <img src="http://placehold.it/350x150">
      </a>
      <h3>Vessel: Panorama</h3>
      <div class="departure-card">
        <p>Havana to Cienfuegos starTing at $5,999</p>
        <a href="#" class="btn btn-explore">Explore</a>
      </div>
      <div class="departure-card">
        <p>Havana to Cienfuegos starTing at $5,999</p>
        <a href="cienfuegos-from-havana.html" class="btn btn-explore">Explore</a>
      </div>
    </div>
  </div>
</div>