<span><span class="va">flights</span><span class="op">[</span><span class="va">carrier</span> <span class="op">==</span> <span class="st">"AA"</span>, <span class="va">.N</span>, by <span class="op">=</span> <span class="fu">.</span><span class="op">(</span><span class="va">origin</span>, <span class="va">dest</span><span class="op">)</span><span class="op">]</span><span class="op">[</span><span class="fu"><a href="https://rdrr.io/r/base/order.html" class="external-link">order</a></span><span class="op">(</