''He reminds me of a laser beam, cutting through complexities of some of the toughest problems that we face,'' Secretary of Transportation Elizabeth Dole said of her husband in Ottumwa, Iowa, during one of at least 21 road days last month boosting Sen. Robert J. Dole's presidential candi-dacy.

While back in Washington her department copes with an aviation crisis, she travels almost constantly. Although the Transportation Department gives her travel schedule a top-secret, eyes-only classification, government documents and newspaper clippings expose an itinerary that emphasizes early delegate-selection states: Iowa, New Hampshire and the March 8 Super Tuesday states.

A document dated July 30 showed advance travel scheduling for 11 days in September, 14 days in October and six days already blocked out for November. At October's end, she swings through five Super Tuesday states -- Tennessee, Alabama, North Carolina, Florida and Missouri -- during two weeks.

Less than half her itinerary consists of nonpolitical events, few of them transportation-related. Instead, she talks about both her husband's campaign and her own job. A Dole-for-president lawyer told us the campaign pays for travels that are deemed to be strictly in the senator's behalf.

But that does not include ''incidental'' activity for the senator, plus just plain advertising of the Dole name in primary states by the most charming member of President Reagan's Cabinet. The taxpayer pays there. To remove such ambiguities, should she resign from the Cabinet?

''At this point, there is no reason,'' Dole campaign consultant Dave Keene told us. ''I told her that unless other executive branch officials resign their jobs, she should not give up hers.'' That tongue-in-cheek reference was to Vice President George Bush, who is preceding announcement of his candidacy with a long, taxpayer-financed tour of Europe.

Bush campaign officials claim the vice president's campaign pays entirely for anything even partly political, while the Dole campaign does not. In fact, the campaign shelled out $25,452 for her August travels. Even when her husband picks up the tab, she includes his-and-her themes, which can give the impression she is on a government mission mixing in a little politics.

Thus, on her Aug. 20 visit to Tuscaloosa, Ala., she praised the senator at a campaign fund-raiser (''he's in a position to get the ball across the goal line") but talked about air safety and the Detroit air crash in addressing the University of Alabama Law School.

Another example was the secretary's five-city swing last month through Iowa, which included the ''laser beam'' comment in Ottumwa. She also talked about such government business as air safety and drug testing in her department.

Her stops in the nation's two most populous but later delegate-selecting states, New York and California, are rare (one in each state scheduled so far between Aug. 1 and year's end). But Iowa is proving irresistible. She was there again yesterday. According to Transportation Department documents, she will be in Ames as part of a general statewide tour Sept. 26 and back yet again on Oct. 17. No events are listed. Queries to the department whether she plans to conduct government business went unanswered.

But she need not campaign overtly to help her husband. Thus, on a taxpayer-financed swing through Iowa May 24, she reassured Waterloo and Dubuque that she will not leave them without an air carrier to Chicago. In far-off New Hampshire a few days later, Laconia received a similar boost. The Transportation Department unexpectedly approved a subsidy to guarantee an airline will operate out of that town -- a benefit with the name Dole written all over it.

Indeed, New Hampshire is one of Secretary Dole's favorite places. She was there Aug. 8, again from Aug. 14 through Aug. 17, and will be back Sept. 18 and again on Oct. 12.

Liddy Dole is not merely a messenger carrying promises of small-town airline service and reassurances of airline safety. She is high political glamour and one of the Republican Party's most charismatic figures, guaranteed to entrance potential primary voters.

Any presidential hopeful would pray for such a wife and such wonderful help. Nevertheless, the senator's opponents question whether that is really the proper role for the secretary of transportation, particularly during so troubled a time for the nation's aviation system and so difficult a time for her own department.