You cannot embed an echo statement within another echo like that. Either use concatenation (using the "." operator) like you did elsewhere, or you might want to consider doing something like the following, which also provides more robust functionality:
printf('<tr>
<td><p style="font-size:x-small;">
<a href="flightplans.php?division=%s&aircraft=%s" STYLE="TEXT-DECORATION: NONE">%s</a>
</p></td>
</tr>',
urlencode($division),
urlencode($row['Aircraft']),
htmlentities($row['Aircraft'])
);