Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Aerodynamics Inc.
Table title:
Destinations
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Country (State/Province) </th><th colspan=1 rowspan=1 > City </th><th colspan=1 rowspan=1 > Airport </th><th colspan=1 rowspan=1 > Begin </th><th colspan=1 rowspan=1 > End </th><th colspan=1 rowspan=1 > Notes </th></tr>
<tr> <td colspan=1 rowspan=1 > United States (Colorado) </td><td colspan=1 rowspan=1 > Denver </td><td colspan=1 rowspan=1 > Denver International Airport </td><td colspan=1 rowspan=1 > 2014 </td><td colspan=1 rowspan=1 > Present </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > United States (South Dakota) </td><td colspan=1 rowspan=1 > Pierre </td><td colspan=1 rowspan=1 > Pierre Regional Airport </td><td colspan=1 rowspan=1 > 2014 </td><td colspan=1 rowspan=1 > 2019 </td><td colspan=1 rowspan=1 > Essential Air Service </td></tr>
<tr> <td colspan=1 rowspan=1 > United States (South Dakota) </td><td colspan=1 rowspan=1 > Watertown </td><td colspan=1 rowspan=1 > Watertown Regional Airport </td><td colspan=1 rowspan=1 > 2015 </td><td colspan=1 rowspan=1 > 2019 </td><td colspan=1 rowspan=1 > Essential Air Service </td></tr>
<tr> <td colspan=1 rowspan=1 > United States (Illinois) </td><td class="highlighted"  colspan=1 rowspan=1 > Chicago </td><td class="highlighted"  colspan=1 rowspan=1 > O'Hare International Airport </td><td class="highlighted"  colspan=1 rowspan=1 > 2016 </td><td colspan=1 rowspan=1 > 2017 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > United States (Ohio) </td><td class="highlighted"  colspan=1 rowspan=1 > Youngstown </td><td class="highlighted"  colspan=1 rowspan=1 > Youngstown–Warren Regional Airport </td><td class="highlighted"  colspan=1 rowspan=1 > 2016 </td><td colspan=1 rowspan=1 > 2017 </td><td colspan=1 rowspan=1 >  </td></tr>
</table>
Question:
Which cities did Aerodynamics Inc. offer flights to in 2018?
Answer:
In 2018, Aerodynamics Inc. offered flights to Denver, Colorado, Pierre, South Dakota, and Watertown, South Dakota.